diff --git a/Engine/AppManager.cpp b/Engine/AppManager.cpp
index 586c5e303..8712eec00 100644
--- a/Engine/AppManager.cpp
+++ b/Engine/AppManager.cpp
@@ -457,9 +457,15 @@ AppManager::~AppManager()
     QThreadPool::globalInstance()->waitForDone();
 
     ///Kill caches now because decreaseNCacheFilesOpened can be called
-    _imp->_nodeCache->waitForDeleterThread();
-    _imp->_diskCache->waitForDeleterThread();
-    _imp->_viewerCache->waitForDeleterThread();
+    if (_imp->_nodeCache) {
+        _imp->_nodeCache->waitForDeleterThread();
+    }
+    if (_imp->_diskCache) {
+        _imp->_diskCache->waitForDeleterThread();
+    }
+    if (_imp->_viewerCache) {
+        _imp->_viewerCache->waitForDeleterThread();
+    }
     _imp->_nodeCache.reset();
     _imp->_viewerCache.reset();
     _imp->_diskCache.reset();
diff --git a/Engine/AppManagerPrivate.cpp b/Engine/AppManagerPrivate.cpp
index 55922950c..6f396a3cb 100644
--- a/Engine/AppManagerPrivate.cpp
+++ b/Engine/AppManagerPrivate.cpp
@@ -448,6 +448,10 @@ template <typename T>
 void
 saveCache(Cache<T>* cache)
 {
+    if (!cache) {
+        return;
+    }
+
     std::string cacheRestoreFilePath = cache->getRestoreFilePath();
     FStreamsSupport::ofstream ofile;
     FStreamsSupport::open(&ofile, cacheRestoreFilePath);