diff --git a/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp b/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
index 7609b335843..060f4ce5e8e 100644
--- a/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
+++ b/mozilla/mailnews/db/msgdb/src/nsMsgDatabase.cpp
@@ -1697,7 +1697,7 @@ NS_IMETHODIMP nsMsgDatabase::ListAllKeys(nsMsgKeyArray &outputKeys)
 
 			err = rowCursor->NextRowOid(GetEnv(), &outOid, &outPos);
 			// is this right? Mork is returning a 0 id, but that should valid.
-			if (outPos < 0 || outOid.mOid_Id == -1)	
+			if (outPos < 0 || outOid.mOid_Id == (mdb_id) -1)	
 				break;
 			if (err == NS_OK)
 				outputKeys.Add(outOid.mOid_Id);