diff --git a/fsw/cfe-core/unit-test/es_UT.c b/fsw/cfe-core/unit-test/es_UT.c
index 1604ae50e..dddfb8ddb 100644
--- a/fsw/cfe-core/unit-test/es_UT.c
+++ b/fsw/cfe-core/unit-test/es_UT.c
@@ -727,7 +727,7 @@ void TestStartupErrorPaths(void)
 
     /* Perform ES main startup with a mutex creation failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_MutSemCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_MutSemCreate), OS_ERROR);
     UT_SetReadBuffer(StartupScript, strlen(StartupScript));
     UT_SetDataBuffer(UT_KEY(CFE_PSP_Panic), &PanicStatus, sizeof(PanicStatus), false);
     CFE_ES_Main(CFE_PSP_RST_TYPE_POWERON, 1, 1,
@@ -741,7 +741,7 @@ void TestStartupErrorPaths(void)
     /* Perform ES main startup with a file open failure */
     ES_ResetUnitTest();
     UT_SetDummyFuncRtn(OS_SUCCESS);
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_SetHookFunction(UT_KEY(OS_TaskCreate), ES_UT_SetAppStateHook, NULL);
     CFE_ES_Main(CFE_PSP_RST_TYPE_POWERON, 1, 1,
                 (char *) CFE_PLATFORM_ES_NONVOL_STARTUP_FILE);
@@ -875,9 +875,9 @@ void TestStartupErrorPaths(void)
      * following a failure to create the RAM volume
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_initfs), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_mount), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_mkfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_initfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mount), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mkfs), OS_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_POWERON);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_CREATE_VOLATILE]) &&
@@ -890,9 +890,9 @@ void TestStartupErrorPaths(void)
      * following a failure to reformat the RAM volume
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_initfs), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_mount), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_mkfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_initfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mount), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mkfs), OS_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_INSUFF_FREE_SPACE]) &&
@@ -908,7 +908,7 @@ void TestStartupErrorPaths(void)
      * following failure to get the volatile disk memory
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(CFE_PSP_GetVolatileDiskMem), CFE_PSP_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_GetVolatileDiskMem), CFE_PSP_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_INSUFF_FREE_SPACE]) &&
@@ -920,7 +920,7 @@ void TestStartupErrorPaths(void)
      * reported is greater than the number of RAM disk sectors
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_mount), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mount), OS_ERROR);
     UT_SetDeferredRetcode(UT_KEY(OS_fsBlocksFree), 1, CFE_PLATFORM_ES_RAM_DISK_NUM_SECTORS + 1);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
@@ -933,7 +933,7 @@ void TestStartupErrorPaths(void)
      * following a failure to remove the RAM volume
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_rmfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_rmfs), OS_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_INSUFF_FREE_SPACE]) &&
@@ -967,7 +967,7 @@ void TestStartupErrorPaths(void)
      * following a failure to remount the RAM volume
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_mount), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mount), OS_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_INSUFF_FREE_SPACE]) &&
@@ -1037,8 +1037,8 @@ void TestStartupErrorPaths(void)
      * creating a core app
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_BinSemCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_BinSemCreate), OS_ERROR);
     UT_SetHookFunction(UT_KEY(OS_TaskCreate), ES_UT_SetAppStateHook, NULL);
     CFE_ES_CreateObjects();
     UT_Report(__FILE__, __LINE__,
@@ -1104,8 +1104,8 @@ void TestStartupErrorPaths(void)
      * following a failure to initialize and mount the RAM volume
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_initfs), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_mount), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_initfs), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_mount), OS_ERROR);
     CFE_ES_InitializeFileSystems(CFE_PSP_RST_TYPE_PROCESSOR);
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_INSUFF_FREE_SPACE]) &&
@@ -1235,7 +1235,7 @@ void TestApps(void)
 
     /* Test starting an application with an open failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     CFE_ES_StartApplications(CFE_PSP_RST_TYPE_PROCESSOR,
                              CFE_PLATFORM_ES_NONVOL_STARTUP_FILE);
     UT_Report(__FILE__, __LINE__,
@@ -1282,7 +1282,7 @@ void TestApps(void)
 
     /* Test application loading and creation with a task creation failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
     Return = CFE_ES_AppCreate(&Id,
                               "ut/filename",
                               "EntryPoint",
@@ -1569,7 +1569,8 @@ void TestApps(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, NULL);
     UtAppRecPtr->ControlReq.AppControlRequest =
         CFE_ES_RunStatus_SYS_RESTART;
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
+    OS_ModuleLoad(&UtAppRecPtr->ModuleInfo.ModuleId, NULL, NULL, 0);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
     Id = CFE_ES_AppRecordGetID(UtAppRecPtr);
     CFE_ES_ProcessControlRequest(Id);
     UT_Report(__FILE__, __LINE__,
@@ -1599,7 +1600,8 @@ void TestApps(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, NULL);
     UtAppRecPtr->ControlReq.AppControlRequest =
         CFE_ES_RunStatus_SYS_RELOAD;
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
+    OS_ModuleLoad(&UtAppRecPtr->ModuleInfo.ModuleId, NULL, NULL, 0);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
     Id = CFE_ES_AppRecordGetID(UtAppRecPtr);
     CFE_ES_ProcessControlRequest(Id);
     UT_Report(__FILE__, __LINE__,
@@ -1797,8 +1799,9 @@ void TestApps(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, NULL);
     ES_UT_SetupForOSCleanup();
 
-    UT_SetForceFail(UT_KEY(OS_TaskDelete), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_close), OS_ERROR);
+    OS_ModuleLoad(&UtAppRecPtr->ModuleInfo.ModuleId, NULL, NULL, 0);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskDelete), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_close), OS_ERROR);
     Id = CFE_ES_AppRecordGetID(UtAppRecPtr);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_CleanUpApp(Id) == CFE_ES_APP_CLEANUP_ERR,
@@ -1924,7 +1927,7 @@ void TestApps(void)
     Id = CFE_ES_TaskRecordGetID(UtTaskRecPtr);
     ES_UT_SetupForOSCleanup();
     UT_SetDeferredRetcode(UT_KEY(OS_TimerGetInfo), 1, OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_close), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_close), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_CleanupTaskResources(Id) != CFE_SUCCESS,
               "CFE_ES_CleanupTaskResources",
@@ -1937,7 +1940,7 @@ void TestApps(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, NULL, &UtTaskRecPtr);
     Id = CFE_ES_TaskRecordGetID(UtTaskRecPtr);
     UT_SetDeferredRetcode(UT_KEY(OS_TimerGetInfo), 1, OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_TaskDelete), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskDelete), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_CleanupTaskResources(Id) == CFE_ES_TASK_DELETE_ERR,
               "CFE_ES_CleanupTaskResources",
@@ -2061,7 +2064,7 @@ void TestApps(void)
     /* switch the main task association (makes it wrong) */
     UtAppRecPtr->MainTaskId = CFE_ES_TaskRecordGetID(UtTaskRecPtr);
 
-    UT_SetForceFail(UT_KEY(OS_TaskDelete), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskDelete), OS_ERROR);
     Id = CFE_ES_AppRecordGetID(UtAppRecPtr);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_CleanUpApp(Id) == CFE_ES_APP_CLEANUP_ERR,
@@ -2280,8 +2283,8 @@ void TestLibs(void)
      * initialization function fails and then must be cleaned up
      */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_remove), OS_ERROR); /* for coverage of error path */
-    UT_SetForceFail(UT_KEY(dummy_function), -555);
+    UT_SetDefaultReturnValue(UT_KEY(OS_remove), OS_ERROR); /* for coverage of error path */
+    UT_SetDefaultReturnValue(UT_KEY(dummy_function), -555);
     Return = CFE_ES_LoadLibrary(&Id,
                                 "/cf/apps/tst_lib.bundle",
                                 "dummy_function",
@@ -2674,7 +2677,7 @@ void TestTask(void)
 
     /* Test task main process loop with an initialization failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskRegister), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskRegister), OS_ERROR);
     CFE_ES_TaskMain();
     UT_Report(__FILE__, __LINE__,
               UT_PrintfIsInHistory(UT_OSP_MESSAGES[UT_OSP_APP_INIT]),
@@ -2727,7 +2730,7 @@ void TestTask(void)
 
     /* Test task main process loop with a register app failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskRegister), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskRegister), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_TaskInit() == CFE_ES_ERR_APP_REGISTER,
              "CFE_ES_TaskInit",
@@ -2876,7 +2879,7 @@ void TestTask(void)
 
     /* Test app create with an OS task create failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_StartApp_t),
             UT_TPID_CFE_ES_CMD_START_APP_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3190,7 +3193,7 @@ void TestTask(void)
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
     ES_UT_SetupSingleAppId(CFE_ES_AppType_CORE, CFE_ES_AppState_RUNNING, "CFE_ES", NULL, NULL);
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_QueryAll_t),
             UT_TPID_CFE_ES_CMD_QUERY_ALL_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3202,7 +3205,7 @@ void TestTask(void)
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
     ES_UT_SetupSingleAppId(CFE_ES_AppType_CORE, CFE_ES_AppState_RUNNING, "CFE_ES", NULL, NULL);
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_QueryAll_t),
             UT_TPID_CFE_ES_CMD_QUERY_ALL_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3238,7 +3241,7 @@ void TestTask(void)
     ES_ResetUnitTest();
     ES_UT_SetupSingleAppId(CFE_ES_AppType_CORE, CFE_ES_AppState_RUNNING, "UT", NULL, NULL);
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_QueryAllTasks_t),
             UT_TPID_CFE_ES_CMD_QUERY_ALL_TASKS_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3249,7 +3252,7 @@ void TestTask(void)
     /* Test write of all task data to a file with an OS create failure */
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_QueryAllTasks_t),
             UT_TPID_CFE_ES_CMD_QUERY_ALL_TASKS_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3316,7 +3319,7 @@ void TestTask(void)
     /* Test writing the system log with an OS create failure */
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     strncpy((char *) CmdBuf.WriteSyslogCmd.Payload.FileName, "",
             sizeof(CmdBuf.WriteSyslogCmd.Payload.FileName));
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_WriteSyslog_t),
@@ -3329,7 +3332,7 @@ void TestTask(void)
     /* Test writing the system log with an OS write failure */
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     CFE_ES_ResetDataPtr->SystemLogWriteIdx = snprintf(CFE_ES_ResetDataPtr->SystemLog,
             sizeof(CFE_ES_ResetDataPtr->SystemLog),
             "0000-000-00:00:00.00000 Test Message\n");
@@ -3421,7 +3424,7 @@ void TestTask(void)
     /* Test writing the E&R log with an OS create failure */
     ES_ResetUnitTest();
     CFE_ES_TaskData.BackgroundERLogDumpState.IsPending = true;
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     CFE_ES_RunERLogDump(0, &CFE_ES_TaskData.BackgroundERLogDumpState);
     UT_Report(__FILE__, __LINE__,
               UT_EventIsInHistory(CFE_ES_ERLOG2_ERR_EID),
@@ -3431,7 +3434,7 @@ void TestTask(void)
     /* Test writing the E&R log with an OS write failure */
     ES_ResetUnitTest();
     CFE_ES_TaskData.BackgroundERLogDumpState.IsPending = true;
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     CFE_ES_RunERLogDump(0, &CFE_ES_TaskData.BackgroundERLogDumpState);
     UT_Report(__FILE__, __LINE__,
               UT_EventIsInHistory(CFE_ES_FILEWRITE_ERR_EID),
@@ -3450,7 +3453,7 @@ void TestTask(void)
 
     /* Test scan for exceptions in the PSP, should invoke a Processor Reset */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(CFE_PSP_Exception_GetCount), 1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_Exception_GetCount), 1);
     CFE_ES_RunExceptionScan(0, NULL);
     UT_Report(__FILE__, __LINE__,
             UT_GetStubCount(UT_KEY(CFE_PSP_Restart)) == 1,
@@ -3460,7 +3463,7 @@ void TestTask(void)
     ES_ResetUnitTest();
     CFE_ES_ResetDataPtr->ResetVars.ProcessorResetCount = 0;
     CFE_ES_ResetDataPtr->ResetVars.MaxProcessorResetCount = 1;
-    UT_SetForceFail(UT_KEY(CFE_PSP_Exception_GetCount), 1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_Exception_GetCount), 1);
     CFE_ES_RunExceptionScan(0, NULL);
     /* first time should do a processor restart (limit reached) */
     UT_Report(__FILE__, __LINE__,
@@ -3476,7 +3479,7 @@ void TestTask(void)
 
     /* nominal for app restart - associate exception with a task ID */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(CFE_PSP_Exception_GetCount), 1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_Exception_GetCount), 1);
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, &UtTaskRecPtr);
     UT_ContextTask = CFE_ES_ResourceID_ToOSAL(CFE_ES_TaskRecordGetID(UtTaskRecPtr));
     UT_SetDataBuffer(UT_KEY(CFE_PSP_Exception_GetSummary), &UT_ContextTask, sizeof(UT_ContextTask), false);
@@ -3497,7 +3500,7 @@ void TestTask(void)
 
     /* repeat, but for a CORE app, which cannot be restarted */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(CFE_PSP_Exception_GetCount), 1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_Exception_GetCount), 1);
     ES_UT_SetupSingleAppId(CFE_ES_AppType_CORE, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, &UtTaskRecPtr);
     UT_ContextTask = CFE_ES_ResourceID_ToOSAL(CFE_ES_TaskRecordGetID(UtTaskRecPtr));
     UT_SetDataBuffer(UT_KEY(CFE_PSP_Exception_GetSummary), &UT_ContextTask, sizeof(UT_ContextTask), false);
@@ -3510,7 +3513,7 @@ void TestTask(void)
               "Scan for exceptions; core app, psp restart");
 
     /* check failure of getting summary data */
-    UT_SetForceFail(UT_KEY(CFE_PSP_Exception_GetSummary), CFE_PSP_NO_EXCEPTION_DATA);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_Exception_GetSummary), CFE_PSP_NO_EXCEPTION_DATA);
     CFE_ES_RunExceptionScan(0, NULL);
     UT_Report(__FILE__, __LINE__,
             UT_GetStubCount(UT_KEY(CFE_PSP_Restart)) == 2,
@@ -3635,7 +3638,7 @@ void TestTask(void)
     /* Test dumping of the CDS to a file with an OS create failure */
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_DumpCDSRegistry_t),
             UT_TPID_CFE_ES_CMD_DUMP_CDS_REGISTRY_CC);
     UT_Report(__FILE__, __LINE__,
@@ -3646,7 +3649,7 @@ void TestTask(void)
     /* Test dumping of the CDS to a file with an OS write failure */
     ES_ResetUnitTest();
     memset(&CmdBuf, 0, sizeof(CmdBuf));
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     ES_UT_SetupSingleCDSRegistry("CFE_ES.CDS_NAME", ES_UT_CDS_BLOCK_SIZE, false, NULL);
     UT_CallTaskPipe(CFE_ES_TaskPipe, &CmdBuf.Msg, sizeof(CFE_ES_DumpCDSRegistry_t),
             UT_TPID_CFE_ES_CMD_DUMP_CDS_REGISTRY_CC);
@@ -4385,7 +4388,7 @@ void TestPerf(void)
     memset(&CFE_ES_TaskData.BackgroundPerfDumpState, 0,
                 sizeof(CFE_ES_TaskData.BackgroundPerfDumpState));
     CFE_ES_TaskData.BackgroundPerfDumpState.PendingState = CFE_ES_PerfDumpState_INIT;
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), -10);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), -10);
     CFE_ES_RunPerfLogDump(1000, &CFE_ES_TaskData.BackgroundPerfDumpState);
     UtAssert_True(CFE_ES_TaskData.BackgroundPerfDumpState.CurrentState == CFE_ES_PerfDumpState_IDLE,
             "CFE_ES_RunPerfLogDump - OS create fail, CFE_ES_TaskData.BackgroundPerfDumpState.CurrentState (%d) == IDLE (%d)",
@@ -4397,7 +4400,7 @@ void TestPerf(void)
     ES_ResetUnitTest();
     memset(&CFE_ES_TaskData.BackgroundPerfDumpState, 0,
             sizeof(CFE_ES_TaskData.BackgroundPerfDumpState));
-    UT_SetForceFail(UT_KEY(OS_write), -10);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), -10);
     CFE_ES_TaskData.BackgroundPerfDumpState.PendingState = CFE_ES_PerfDumpState_INIT;
     CFE_ES_RunPerfLogDump(1000, &CFE_ES_TaskData.BackgroundPerfDumpState);
     UtAssert_True(CFE_ES_TaskData.BackgroundPerfDumpState.CurrentState == CFE_ES_PerfDumpState_DELAY,
@@ -4739,7 +4742,7 @@ void TestAPI(void)
               "Get task info by ID; NULL buffer");
 
     /* Test getting task information using the task ID - bad task ID  */
-    UT_SetForceFail(UT_KEY(OS_ObjectIdToArrayIndex), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_ObjectIdToArrayIndex), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_GetTaskInfo(&TaskInfo, TaskId) == CFE_ES_ERR_RESOURCEID_NOT_VALID,
               "CFE_ES_GetTaskInfo",
@@ -4800,7 +4803,7 @@ void TestAPI(void)
     /* Test creating a child task with an OS task create failure */
     ES_ResetUnitTest();
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, NULL, NULL);
-    UT_SetForceFail(UT_KEY(OS_TaskCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskCreate), OS_ERROR);
     Return = CFE_ES_CreateChildTask(&TaskId,
                                     "TaskName",
                                     TestAPI,
@@ -4874,7 +4877,7 @@ void TestAPI(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, NULL);
     ES_UT_SetupChildTaskId(UtAppRecPtr, NULL, &UtTaskRecPtr);
     TestObjId = CFE_ES_ResourceID_ToOSAL(CFE_ES_TaskRecordGetID(UtTaskRecPtr));
-    UT_SetForceFail(UT_KEY(OS_TaskGetId), OS_ObjectIdToInteger(TestObjId)); /* Set context to that of child */
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskGetId), OS_ObjectIdToInteger(TestObjId)); /* Set context to that of child */
     Return = CFE_ES_CreateChildTask(&TaskId,
                                     "TaskName",
                                     TestAPI,
@@ -4912,7 +4915,7 @@ void TestAPI(void)
               "Task ID belongs to a main task");
 
     /* Test deleting a child task with an invalid task ID */
-    UT_SetForceFail(UT_KEY(OS_ObjectIdToArrayIndex), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_ObjectIdToArrayIndex), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_DeleteChildTask(TaskId) == CFE_ES_ERR_RESOURCEID_NOT_VALID,
               "CFE_ES_DeleteChildTask",
@@ -4944,7 +4947,7 @@ void TestAPI(void)
     ES_UT_SetupChildTaskId(UtAppRecPtr, NULL, &UtTaskRecPtr);
     AppId = CFE_ES_AppRecordGetID(UtAppRecPtr); /* the app ID */
     TaskId = CFE_ES_TaskRecordGetID(UtTaskRecPtr); /* the child task ID */
-    UT_SetForceFail(UT_KEY(OS_TaskDelete), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskDelete), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_DeleteChildTask(TaskId) <= 0,
               "CFE_ES_DeleteChildTask",
@@ -4963,7 +4966,7 @@ void TestAPI(void)
     ES_UT_SetupSingleAppId(CFE_ES_AppType_EXTERNAL, CFE_ES_AppState_RUNNING, NULL, &UtAppRecPtr, NULL);
     ES_UT_SetupChildTaskId(UtAppRecPtr, NULL, &UtTaskRecPtr);
     TestObjId = CFE_ES_ResourceID_ToOSAL(CFE_ES_TaskRecordGetID(UtTaskRecPtr));
-    UT_SetForceFail(UT_KEY(OS_TaskGetId), OS_ObjectIdToInteger(TestObjId)); /* Set context to that of child */
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskGetId), OS_ObjectIdToInteger(TestObjId)); /* Set context to that of child */
     CFE_ES_ExitChildTask();
     UT_Report(__FILE__, __LINE__,
               UT_GetStubCount(UT_KEY(OS_TaskExit)) == 1,
@@ -4992,7 +4995,7 @@ void TestAPI(void)
 
     /* Test registering a child task with an OS task register failure */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(OS_TaskRegister), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TaskRegister), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_RegisterChildTask() == CFE_ES_ERR_CHILD_TASK_REGISTER,
               "CFE_ES_RegisterChildTask",
@@ -5652,7 +5655,7 @@ void TestCDS()
 
     /* Test CDS initialization with size not obtainable */
     ES_ResetUnitTest();
-    UT_SetForceFail(UT_KEY(CFE_PSP_GetCDSSize), -1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_GetCDSSize), -1);
     UT_Report(__FILE__, __LINE__,
               CFE_ES_CDS_EarlyInit() == OS_ERROR,
               "CFE_ES_CDS_EarlyInit",
@@ -6743,7 +6746,7 @@ void TestBackground(void)
     ES_ResetUnitTest();
     memset(&CFE_ES_TaskData.BackgroundPerfDumpState, 0,
             sizeof(CFE_ES_TaskData.BackgroundPerfDumpState));
-    UT_SetForceFail(UT_KEY(OS_write), -10);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), -10);
     CFE_ES_TaskData.BackgroundPerfDumpState.CurrentState = CFE_ES_PerfDumpState_INIT;
     UT_SetDeferredRetcode(UT_KEY(OS_BinSemTimedWait), 3, -4);
     CFE_ES_BackgroundTask();
diff --git a/fsw/cfe-core/unit-test/evs_UT.c b/fsw/cfe-core/unit-test/evs_UT.c
index 3290158e4..7a84c2a6e 100644
--- a/fsw/cfe-core/unit-test/evs_UT.c
+++ b/fsw/cfe-core/unit-test/evs_UT.c
@@ -465,7 +465,7 @@ void Test_Init(void)
 
     /* Test task initialization where getting the application ID fails */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppID), -1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppID), -1);
     CFE_EVS_TaskInit();
     UT_Report(__FILE__, __LINE__,
               UT_SyslogIsInHistory(EVS_SYSLOG_MSGS[10]),
@@ -516,7 +516,7 @@ void Test_IllegalAppID(void)
 
     /* Set test up with illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
 
     /* Test registering an event using an illegal application ID */
     UT_Report(__FILE__, __LINE__,
@@ -526,7 +526,7 @@ void Test_IllegalAppID(void)
 
     /* Test unregistering an event using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_Unregister() == CFE_EVS_APP_ILLEGAL_APP_ID,
               "CFE_EVS_Unregister",
@@ -534,7 +534,7 @@ void Test_IllegalAppID(void)
 
     /* Test sending an event using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_SendEvent(0, 0, "NULL") == CFE_EVS_APP_ILLEGAL_APP_ID,
               "CFE_EVS_SendEvent",
@@ -542,7 +542,7 @@ void Test_IllegalAppID(void)
 
     /* Test sending an event using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               EVS_SendEvent(0, 0, "NULL") == CFE_SUCCESS,
               "EVS_SendEvent",
@@ -550,7 +550,7 @@ void Test_IllegalAppID(void)
 
     /* Test sending a timed event using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_SendTimedEvent(time,
                                      0,
@@ -561,7 +561,7 @@ void Test_IllegalAppID(void)
 
     /* Test sending an event with app ID using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_SendEventWithAppID(0,
                                          0,
@@ -572,7 +572,7 @@ void Test_IllegalAppID(void)
 
     /* Test resetting a filter using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_ResetFilter(0) == CFE_EVS_APP_ILLEGAL_APP_ID,
               "CFE_EVS_ResetFilter",
@@ -580,7 +580,7 @@ void Test_IllegalAppID(void)
 
     /* Test resetting all filters using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_ResetAllFilters() == CFE_EVS_APP_ILLEGAL_APP_ID,
               "CFE_EVS_ResetAllFilters",
@@ -588,7 +588,7 @@ void Test_IllegalAppID(void)
 
     /* Test application cleanup using an illegal application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_AppID_ToIndex), CFE_ES_ERR_RESOURCEID_NOT_VALID);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_CleanUpApp(CFE_ES_RESOURCEID_UNDEFINED) ==
                   CFE_EVS_APP_ILLEGAL_APP_ID,
@@ -716,7 +716,7 @@ void Test_FilterRegistration(void)
 
     /* Test filter unregistration with failed ES_putPool */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_PutPoolBuf), -1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_PutPoolBuf), -1);
     UT_SetDeferredRetcode(UT_KEY(CFE_ES_GetAppID), 1, -1);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_Unregister() < 0, "CFE_EVS_Unregister",
@@ -1376,7 +1376,7 @@ void Test_Logging(void)
     /* Test writing a log entry with a create failure */
     UT_InitData();
     UT_SetDeferredRetcode(UT_KEY(OS_MutSemCreate), 1, OS_SUCCESS);
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_WriteLogDataFileCmd(&CmdBuf.logfilecmd) != CFE_SUCCESS,
               "CFE_EVS_WriteLogDataFileCmd",
@@ -1394,7 +1394,7 @@ void Test_Logging(void)
     /* Test writing a log entry with a write failure */
     UT_InitData();
     UT_SetDeferredRetcode(UT_KEY(OS_MutSemCreate), 1, OS_SUCCESS);
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     CFE_EVS_GlobalData.EVS_LogPtr->LogCount = CFE_PLATFORM_EVS_LOG_MAX;
     UT_Report(__FILE__, __LINE__,
               CFE_EVS_WriteLogDataFileCmd(&CmdBuf.logfilecmd) != CFE_SUCCESS,
@@ -1472,7 +1472,7 @@ void Test_WriteApp(void)
     UT_InitData();
     strncpy((char *) CmdBuf.AppDataCmd.Payload.AppDataFilename, "ut_cfe_evs",
             sizeof(CmdBuf.AppDataCmd.Payload.AppDataFilename));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_EVS_DoDispatchCheckEvents(&CmdBuf.AppDataCmd, sizeof(CmdBuf.AppDataCmd),
                UT_TPID_CFE_EVS_CMD_WRITE_APP_DATA_FILE_CC,
                &UT_EVS_EventBuf);
@@ -1483,8 +1483,8 @@ void Test_WriteApp(void)
 
     /* Test writing application data with a write/close failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
-    UT_SetForceFail(UT_KEY(OS_close), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_close), OS_ERROR);
     UT_EVS_DoDispatchCheckEvents(&CmdBuf.AppDataCmd, sizeof(CmdBuf.AppDataCmd),
                UT_TPID_CFE_EVS_CMD_WRITE_APP_DATA_FILE_CC,
                &UT_EVS_EventBuf);
@@ -1509,7 +1509,7 @@ void Test_WriteApp(void)
     UT_InitData();
     strncpy((char *) CmdBuf.AppDataCmd.Payload.AppDataFilename, "AppDataFileName",
             sizeof(CmdBuf.AppDataCmd.Payload.AppDataFilename));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_EVS_DoDispatchCheckEvents(&CmdBuf.AppDataCmd, sizeof(CmdBuf.AppDataCmd),
                UT_TPID_CFE_EVS_CMD_WRITE_APP_DATA_FILE_CC,
                &UT_EVS_EventBuf);
@@ -1561,7 +1561,7 @@ void Test_BadAppCmd(void)
             sizeof(appcmdcmd.Payload.AppName));
 
     /* Test disabling application event types with an unknown application ID */
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appbitcmd, sizeof(appbitcmd),
                UT_TPID_CFE_EVS_CMD_DISABLE_APP_EVENT_TYPE_CC,
                &UT_EVS_EventBuf);
@@ -1572,7 +1572,7 @@ void Test_BadAppCmd(void)
 
     /* Test enabling application event types with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appbitcmd, sizeof(appbitcmd),
                UT_TPID_CFE_EVS_CMD_ENABLE_APP_EVENT_TYPE_CC,
                &UT_EVS_EventBuf);
@@ -1583,7 +1583,7 @@ void Test_BadAppCmd(void)
 
     /* Test disabling application events with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appnamecmd, sizeof(appnamecmd),
                UT_TPID_CFE_EVS_CMD_DISABLE_APP_EVENTS_CC,
                &UT_EVS_EventBuf);
@@ -1594,7 +1594,7 @@ void Test_BadAppCmd(void)
 
     /* Test enabling application events with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appnamecmd, sizeof(appnamecmd),
                UT_TPID_CFE_EVS_CMD_ENABLE_APP_EVENTS_CC,
                &UT_EVS_EventBuf);
@@ -1607,7 +1607,7 @@ void Test_BadAppCmd(void)
      * application ID
      */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appnamecmd, sizeof(appnamecmd),
                UT_TPID_CFE_EVS_CMD_RESET_APP_COUNTER_CC,
                &UT_EVS_EventBuf);
@@ -1618,7 +1618,7 @@ void Test_BadAppCmd(void)
 
     /* Test modifying event filters with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appmaskcmd, sizeof(appmaskcmd),
                UT_TPID_CFE_EVS_CMD_ADD_EVENT_FILTER_CC,
                &UT_EVS_EventBuf);
@@ -1630,7 +1630,7 @@ void Test_BadAppCmd(void)
 
     /* Test deleting event filters with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appcmdcmd, sizeof(appcmdcmd),
                UT_TPID_CFE_EVS_CMD_DELETE_EVENT_FILTER_CC,
                &UT_EVS_EventBuf);
@@ -1642,7 +1642,7 @@ void Test_BadAppCmd(void)
 
     /* Test setting the event filter mask with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appmaskcmd, sizeof(appmaskcmd),
                UT_TPID_CFE_EVS_CMD_SET_FILTER_CC,
                &UT_EVS_EventBuf);
@@ -1654,7 +1654,7 @@ void Test_BadAppCmd(void)
 
     /* Test resetting the filter with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appcmdcmd, sizeof(appcmdcmd),
                UT_TPID_CFE_EVS_CMD_RESET_FILTER_CC,
                &UT_EVS_EventBuf);
@@ -1665,7 +1665,7 @@ void Test_BadAppCmd(void)
 
     /* Test resetting all filters with an unknown application ID */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_GetAppIDByName), CFE_ES_ERR_NAME_NOT_FOUND);
     UT_EVS_DoDispatchCheckEvents(&appnamecmd, sizeof(appnamecmd),
                UT_TPID_CFE_EVS_CMD_RESET_ALL_FILTERS_CC,
                &UT_EVS_EventBuf);
diff --git a/fsw/cfe-core/unit-test/fs_UT.c b/fsw/cfe-core/unit-test/fs_UT.c
index dabd2c3e5..a1b6f5c48 100644
--- a/fsw/cfe-core/unit-test/fs_UT.c
+++ b/fsw/cfe-core/unit-test/fs_UT.c
@@ -95,7 +95,7 @@ void Test_CFE_FS_ReadHeader(void)
 
     /* Test reading the header with a lseek failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_lseek), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_lseek), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_ReadHeader(&Hdr, FileDes) == OS_ERROR,
               "CFE_FS_ReadHeader",
@@ -104,7 +104,7 @@ void Test_CFE_FS_ReadHeader(void)
     /* Test successfully reading the header */
     UT_InitData();
     UT_SetDeferredRetcode(UT_KEY(OS_lseek), 1, OS_SUCCESS);
-    UT_SetForceFail(UT_KEY(OS_read), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_read), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_ReadHeader(&Hdr, FileDes) != sizeof(CFE_FS_Header_t),
               "CFE_FS_ReadHeader",
@@ -123,7 +123,7 @@ void Test_CFE_FS_WriteHeader(void)
 
     /* Test writing the header with a lseek failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_lseek), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_lseek), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_WriteHeader(FileDes, &Hdr) == OS_ERROR,
               "CFE_FS_WriteHeader",
@@ -151,7 +151,7 @@ void Test_CFE_FS_SetTimestamp(void)
 
     /* Test setting the time stamp with a lseek failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_lseek), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_lseek), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_SetTimestamp(FileDes, NewTimestamp) == OS_ERROR,
               "CFE_FS_SetTimestamp",
@@ -159,7 +159,7 @@ void Test_CFE_FS_SetTimestamp(void)
 
     /* Test setting the time stamp with a seconds write failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_write), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_write), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_SetTimestamp(FileDes, NewTimestamp) != OS_SUCCESS,
               "CFE_FS_SetTimestamp",
@@ -313,7 +313,7 @@ void Test_CFE_FS_Private(void)
 
     /* Test FS initialization with a mutex creation failure */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_MutSemCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_MutSemCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_FS_EarlyInit() == -1,
               "CFE_FS_EarlyInit",
diff --git a/fsw/cfe-core/unit-test/sb_UT.c b/fsw/cfe-core/unit-test/sb_UT.c
index f979edb23..f0b44c86d 100644
--- a/fsw/cfe-core/unit-test/sb_UT.c
+++ b/fsw/cfe-core/unit-test/sb_UT.c
@@ -566,7 +566,7 @@ void Test_SB_Cmds_RoutingInfoCreateFail(void)
     CFE_SB.CmdPipePktPtr = (CFE_MSG_Message_t *) &WriteFileCmd;
 
     /* Make function CFE_SB_SendRtgInfo return CFE_SB_FILE_IO_ERR */
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
 
     CFE_SB_ProcessCmdPipePkt();
 
@@ -686,7 +686,7 @@ void Test_SB_Cmds_PipeInfoSpec(void)
 */
 void Test_SB_Cmds_PipeInfoCreateFail(void)
 {
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     ASSERT_EQ(CFE_SB_SendPipeInfo("PipeTstFile"), CFE_SB_FILE_IO_ERR);
 
     EVTCNT(1);
@@ -821,7 +821,7 @@ void Test_SB_Cmds_MapInfoSpec(void)
 */
 void Test_SB_Cmds_MapInfoCreateFail(void)
 {
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     ASSERT_EQ(CFE_SB_SendMapInfo("MapTstFile"), CFE_SB_FILE_IO_ERR);
 
     EVTCNT(1);
diff --git a/fsw/cfe-core/unit-test/tbl_UT.c b/fsw/cfe-core/unit-test/tbl_UT.c
index 7f6baa51c..5c486aa95 100644
--- a/fsw/cfe-core/unit-test/tbl_UT.c
+++ b/fsw/cfe-core/unit-test/tbl_UT.c
@@ -751,7 +751,7 @@ void Test_CFE_TBL_DumpToFile(void)
 
     /* Test with an error creating the dump file */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_TBL_DumpToFile("filename" ,"tablename" ,"dumpaddress",
                                  TblSizeInBytes) == CFE_TBL_INC_ERR_CTR,
@@ -1154,7 +1154,7 @@ void Test_CFE_TBL_DumpRegCmd(void)
     UT_InitData();
     strncpy((char *)DumpRegCmd.Payload.DumpFilename, "",
             sizeof(DumpRegCmd.Payload.DumpFilename));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_TBL_DumpRegistryCmd(&DumpRegCmd) ==
                 CFE_TBL_INC_ERR_CTR,
@@ -1424,7 +1424,7 @@ void Test_CFE_TBL_LoadCmd(void)
     UT_InitData();
     strncpy((char *)LoadCmd.Payload.LoadFilename, "LoadFileName",
             sizeof(LoadCmd.Payload.LoadFilename));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_TBL_LoadCmd(&LoadCmd) ==
                 CFE_TBL_INC_ERR_CTR,
@@ -1705,7 +1705,7 @@ void Test_CFE_TBL_HousekeepingCmd(void)
     UT_InitData();
     CFE_TBL_TaskData.DumpControlBlocks[0].State = CFE_TBL_DUMP_PERFORMED;
     CFE_TBL_TaskData.HkTlmTblRegIndex = CFE_TBL_NOT_FOUND + 1;
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_TBL_HousekeepingCmd(NULL) == CFE_TBL_DONT_INC_CTR,
               "CFE_TBL_HousekeepingCmd",
@@ -1715,7 +1715,7 @@ void Test_CFE_TBL_HousekeepingCmd(void)
     UT_InitData();
     CFE_TBL_TaskData.HkTlmTblRegIndex = CFE_TBL_NOT_FOUND;
     CFE_TBL_TaskData.DumpControlBlocks[0].State = CFE_TBL_DUMP_PERFORMED;
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     UT_Report(__FILE__, __LINE__,
               CFE_TBL_HousekeepingCmd(NULL) == CFE_TBL_DONT_INC_CTR,
               "CFE_TBL_HousekeepingCmd",
@@ -4119,7 +4119,7 @@ void Test_CFE_TBL_Internal(void)
 
     UT_SetReadBuffer(&TblFileHeader, sizeof(TblFileHeader));
     UT_SetReadHeader(&StdFileHeader, sizeof(StdFileHeader));
-    UT_SetForceFail(UT_KEY(OS_OpenCreate), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_OpenCreate), OS_ERROR);
     RtnCode = CFE_TBL_LoadFromFile("UT", WorkingBufferPtr, RegRecPtr, Filename);
     EventsCorrect = (UT_EventIsInHistory(CFE_TBL_FILE_ACCESS_ERR_EID) == true &&
         UT_GetNumEventsSent() == 1);
@@ -4633,7 +4633,7 @@ void Test_CFE_TBL_Internal(void)
     /* Test successful application cleanup */
     UT_InitData();
     UT_SetAppID(UT_TBL_APPID_1);
-    UT_SetForceFail(UT_KEY(CFE_ES_PutPoolBuf), -1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_PutPoolBuf), -1);
     AccessDescPtr = &CFE_TBL_TaskData.Handles[App1TblHandle1];
     RegRecPtr = &CFE_TBL_TaskData.Registry[AccessDescPtr->RegIndex];
     CFE_TBL_TaskData.DumpControlBlocks[3].State = CFE_TBL_DUMP_PENDING;
@@ -4797,7 +4797,7 @@ void Test_CFE_TBL_Internal(void)
      */
     UT_InitData();
     UT_SetAppID(UT_TBL_APPID_1);
-    UT_SetForceFail(UT_KEY(CFE_ES_PutPoolBuf), -1);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_ES_PutPoolBuf), -1);
     CFE_TBL_TaskData.Handles[0].AppId = UT_TBL_APPID_1;
     AccessDescPtr = &CFE_TBL_TaskData.Handles[App1TblHandle2];
     RegRecPtr = &CFE_TBL_TaskData.Registry[AccessDescPtr->RegIndex];
diff --git a/fsw/cfe-core/unit-test/time_UT.c b/fsw/cfe-core/unit-test/time_UT.c
index 211999e51..6fdc94b3f 100644
--- a/fsw/cfe-core/unit-test/time_UT.c
+++ b/fsw/cfe-core/unit-test/time_UT.c
@@ -476,7 +476,7 @@ void Test_Init(void)
 
     /* Test response to a failure to get the ID by name */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_TimeBaseGetIdByName), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TimeBaseGetIdByName), OS_ERROR);
     CFE_TIME_TaskInit();
     UT_Report(__FILE__, __LINE__,
               UT_GetStubCount(UT_KEY(CFE_ES_WriteToSysLog)) == 0,
@@ -488,7 +488,7 @@ void Test_Init(void)
      * error.  This allows the overall system to continue without the 1Hz
      */
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_TimerAdd), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TimerAdd), OS_ERROR);
     CFE_TIME_TaskInit();
     UT_Report(__FILE__, __LINE__,
               UT_GetStubCount(UT_KEY(CFE_ES_WriteToSysLog)) == 1 &&
@@ -497,7 +497,7 @@ void Test_Init(void)
               "1Hz OS_TimerAdd failure");
 
     UT_InitData();
-    UT_SetForceFail(UT_KEY(OS_TimerSet), OS_ERROR);
+    UT_SetDefaultReturnValue(UT_KEY(OS_TimerSet), OS_ERROR);
     CFE_TIME_TaskInit();
     UT_Report(__FILE__, __LINE__,
               UT_GetStubCount(UT_KEY(CFE_ES_WriteToSysLog)) == 1 && UT_SyslogIsInHistory((TIME_SYSLOG_MSGS[4])),
diff --git a/fsw/cfe-core/unit-test/ut_support.c b/fsw/cfe-core/unit-test/ut_support.c
index f1e7c4ceb..9a2fd8e80 100644
--- a/fsw/cfe-core/unit-test/ut_support.c
+++ b/fsw/cfe-core/unit-test/ut_support.c
@@ -282,7 +282,7 @@ void UT_SetStatusBSPResetArea(int32 status, uint32 Signature, uint32 ClockSignal
     UT_CFE_ES_ResetData.ResetData.TimeResetVars.ClockSignal = ClockSignal;
     if (status != 0)
     {
-        UT_SetForceFail(UT_KEY(CFE_PSP_GetResetArea), status);
+        UT_SetDefaultReturnValue(UT_KEY(CFE_PSP_GetResetArea), status);
     }
     else
     {
@@ -311,7 +311,7 @@ void UT_SetReadHeader(void *Hdr, int NumBytes)
 */
 void UT_SetDummyFuncRtn(int Return)
 {
-    UT_SetForceFail(UT_KEY(dummy_function), Return);
+    UT_SetDefaultReturnValue(UT_KEY(dummy_function), Return);
 }
 
 /*
diff --git a/modules/sbr/unit-test-coverage/test_cfe_sbr_map_direct.c b/modules/sbr/unit-test-coverage/test_cfe_sbr_map_direct.c
index 770553027..c78c41e2a 100644
--- a/modules/sbr/unit-test-coverage/test_cfe_sbr_map_direct.c
+++ b/modules/sbr/unit-test-coverage/test_cfe_sbr_map_direct.c
@@ -48,7 +48,7 @@ void Test_SBR_Map_Direct(void)
     CFE_SBR_Init_Map();
 
     /* Force valid msgid responses */
-    UT_SetForceFail(UT_KEY(CFE_SB_IsValidMsgId), true);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_SB_IsValidMsgId), true);
 
     UtPrintf("Check that all entries are set invalid");
     count = 0;
diff --git a/modules/sbr/unit-test-coverage/test_cfe_sbr_map_hash.c b/modules/sbr/unit-test-coverage/test_cfe_sbr_map_hash.c
index df78f55c6..1ba6c0db2 100644
--- a/modules/sbr/unit-test-coverage/test_cfe_sbr_map_hash.c
+++ b/modules/sbr/unit-test-coverage/test_cfe_sbr_map_hash.c
@@ -67,7 +67,7 @@ void Test_SBR_Map_Hash(void)
     CFE_SBR_Init();
 
     /* Force valid msgid responses */
-    UT_SetForceFail(UT_KEY(CFE_SB_IsValidMsgId), true);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_SB_IsValidMsgId), true);
 
     UtPrintf("Check that all entries are set invalid");
     count = 0;
diff --git a/modules/sbr/unit-test-coverage/test_cfe_sbr_route_unsorted.c b/modules/sbr/unit-test-coverage/test_cfe_sbr_route_unsorted.c
index ac44c2ec7..2c202d6e0 100644
--- a/modules/sbr/unit-test-coverage/test_cfe_sbr_route_unsorted.c
+++ b/modules/sbr/unit-test-coverage/test_cfe_sbr_route_unsorted.c
@@ -60,7 +60,7 @@ void Test_SBR_Route_Unsort_General(void)
      * Note from here on msgids must be in the valid range since validation is forced true
      * and if the underlying map implentation is direct it needs to be a valid array index
      */
-    UT_SetForceFail(UT_KEY(CFE_SB_IsValidMsgId), true);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_SB_IsValidMsgId), true);
 
     UtPrintf("Callback test with no routes");
     count = 0;
@@ -137,7 +137,7 @@ void Test_SBR_Route_Unsort_GetSet(void)
      * Note from here on msgids must be in the valid range since validation is forced true
      * and if the underlying map implentation is direct it needs to be a valid array index
      */
-    UT_SetForceFail(UT_KEY(CFE_SB_IsValidMsgId), true);
+    UT_SetDefaultReturnValue(UT_KEY(CFE_SB_IsValidMsgId), true);
 
     UtPrintf("Initialize map and route");
     CFE_SBR_Init();