Index: /trunk/src/VBox/Main/src-client/xpcom/module.cpp
===================================================================
--- /trunk/src/VBox/Main/src-client/xpcom/module.cpp	(revision 46823)
+++ /trunk/src/VBox/Main/src-client/xpcom/module.cpp	(revision 46824)
@@ -93,6 +93,7 @@
 NS_IMPL_THREADSAFE_ISUPPORTS1_CI(VRDEServerInfo, IVRDEServerInfo)
 #ifdef VBOX_WITH_EXTPACK
-NS_DECL_CLASSINFO(ExtPackFile)
-NS_IMPL_THREADSAFE_ISUPPORTS2_CI(ExtPackFile, IExtPackFile, IExtPackBase)
+// deliberately omit ExtPackFile as it's unusable in the client context
+// NS_DECL_CLASSINFO(ExtPackFile)
+// NS_IMPL_THREADSAFE_ISUPPORTS2_CI(ExtPackFile, IExtPackFile, IExtPackBase)
 NS_DECL_CLASSINFO(ExtPack)
 NS_IMPL_THREADSAFE_ISUPPORTS2_CI(ExtPack, IExtPack, IExtPackBase)