diff --git a/mozilla/uriloader/exthandler/nsExternalHelperAppService.cpp b/mozilla/uriloader/exthandler/nsExternalHelperAppService.cpp
index f9d35198d5b..bfefde9163e 100644
--- a/mozilla/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/mozilla/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -894,7 +894,7 @@ void nsExternalAppHandler::ExtractSuggestedFileNameFromChannel(nsIChannel* aChan
           // The filename must be ASCII, see RFC 2183, section 2.3
           CopyASCIItoUCS2(Substring(start, iter), mSuggestedFileName);
 
-#ifdef XP_WIN
+#ifndef XP_MAC
           // Make sure extension is still correct.
           EnsureSuggestedFileName();
 #endif
@@ -1034,7 +1034,7 @@ nsresult nsExternalAppHandler::SetUpTempFile(nsIChannel * aChannel)
       NS_UnescapeURL(leafName);
       mSuggestedFileName = NS_ConvertUTF8toUCS2(leafName); // XXX leafName may not be UTF-8
 
-#ifdef XP_WIN
+#ifndef XP_MAC
       // Make sure extension is still correct.
       EnsureSuggestedFileName();
 #endif