diff --git a/lib/clif-backend/src/signal/windows.rs b/lib/clif-backend/src/signal/windows.rs
index ec1c82e9c64..7d3e81d695f 100644
--- a/lib/clif-backend/src/signal/windows.rs
+++ b/lib/clif-backend/src/signal/windows.rs
@@ -71,13 +71,17 @@ pub fn call_protected(
                 TrapCode::HeapOutOfBounds => ExceptionCode::MemoryOutOfBounds,
                 TrapCode::TableOutOfBounds => ExceptionCode::CallIndirectOOB,
                 TrapCode::UnreachableCodeReached => ExceptionCode::Unreachable,
-                _ => ExceptionCode::Unknown,
+                _ => return Err(CallProtError(Box::new("unknown trap code".to_string()))),
             },
-            EXCEPTION_STACK_OVERFLOW => ExceptionCode::Unknown,
+            EXCEPTION_STACK_OVERFLOW => ExceptionCode::MemoryOutOfBounds,
             EXCEPTION_INT_DIVIDE_BY_ZERO | EXCEPTION_INT_OVERFLOW => {
                 ExceptionCode::IllegalArithmetic
             }
-            _ => ExceptionCode::Unknown,
+            _ => {
+                return Err(CallProtError(Box::new(
+                    "unknown exception code".to_string(),
+                )))
+            }
         })))
     } else {
         let signal = match code as DWORD {
diff --git a/lib/spectests/tests/semantics.rs b/lib/spectests/tests/semantics.rs
index bdec931ede7..2edfa7cd1c4 100644
--- a/lib/spectests/tests/semantics.rs
+++ b/lib/spectests/tests/semantics.rs
@@ -30,10 +30,8 @@ mod tests {
         match result {
             Err(err) => match err {
                 CallError::Runtime(RuntimeError(e)) => {
-                    let exc_code = e
-                        .downcast::<ExceptionCode>()
+                    e.downcast::<ExceptionCode>()
                         .expect("expecting exception code");
-                    assert!(exc_code != ExceptionCode::Unknown);
                 }
                 _ => unimplemented!(),
             },
diff --git a/lib/spectests/tests/spectest.rs b/lib/spectests/tests/spectest.rs
index 5f8921613bd..f8b7939f372 100644
--- a/lib/spectests/tests/spectest.rs
+++ b/lib/spectests/tests/spectest.rs
@@ -690,7 +690,7 @@ mod tests {
                                     }
                                     CallError::Runtime(RuntimeError(e)) => {
                                         use wasmer_runtime::ExceptionCode;
-                                        if let Some(_) = data.downcast_ref::<ExceptionCode>() {
+                                        if let Some(_) = e.downcast_ref::<ExceptionCode>() {
                                             test_report.count_passed();
                                         } else {
                                             test_report.add_failure(
@@ -699,8 +699,7 @@ mod tests {
                                                     line,
                                                     kind: format!("{}", "AssertTrap"),
                                                     message: format!(
-                                                        "expected trap, got Runtime:Error {:?}",
-                                                        r
+                                                        "expected trap, got RuntimeError"
                                                     ),
                                                 },
                                                 &test_key,