--- a/storage/src/mozStorageService.cpp
+++ b/storage/src/mozStorageService.cpp
@@ -297,17 +297,17 @@ mozStorageService::BackupDatabaseFile(ns
 
     nsAutoString fileName;
     rv = backupDB->GetLeafName(fileName);
     NS_ENSURE_SUCCESS(rv, rv);
 
     rv = backupDB->Remove(PR_FALSE);
     NS_ENSURE_SUCCESS(rv, rv);
 
-    backupDB.swap(*backup);
+    backupDB.forget(backup);
 
     return aDBFile->CopyTo(parentDir, fileName);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 //// nsIObserver
 
 NS_IMETHODIMP