diff --git a/src/Format/FormatCom.cpp b/src/Format/FormatCom.cpp
index df0fc1e9..ea9c8fed 100644
--- a/src/Format/FormatCom.cpp
+++ b/src/Format/FormatCom.cpp
@@ -35,7 +35,7 @@ public:
 		InterlockedIncrement (&ObjectCount);
 	}
 
-	~TrueCryptFormatCom ()
+	virtual ~TrueCryptFormatCom ()
 	{
 		if (InterlockedDecrement (&ObjectCount) == 0)
 			PostThreadMessage (MessageThreadId, WM_APP, 0, 0);
diff --git a/src/Mount/MainCom.cpp b/src/Mount/MainCom.cpp
index ed1fd68d..0ac0253e 100644
--- a/src/Mount/MainCom.cpp
+++ b/src/Mount/MainCom.cpp
@@ -31,7 +31,7 @@ public:
 		InterlockedIncrement (&ObjectCount);
 	}
 
-	~TrueCryptMainCom ()
+	virtual ~TrueCryptMainCom ()
 	{
 		if (InterlockedDecrement (&ObjectCount) == 0)
 			PostThreadMessage (MessageThreadId, WM_APP, 0, 0);