diff --git a/offlineimap/folder/Gmail.py b/offlineimap/folder/Gmail.py
index bf040e9..48460d9 100644
--- a/offlineimap/folder/Gmail.py
+++ b/offlineimap/folder/Gmail.py
@@ -99,7 +99,14 @@ class GmailFolder(IMAPFolder):
 
         needupdate = copy(uidlist)
         for result in r:
+            if result == None:
+                # Compensate for servers that don't return anything from
+                # STORE.
+                continue
             attributehash = imaputil.flags2hash(imaputil.imapsplit(result)[1])
+            if not ('UID' in attributehash and 'FLAGS' in attributehash):
+                # Compensate for servers that don't return a UID attribute.
+                continue
             flags = attributehash['FLAGS']
             uid = long(attributehash['UID'])
             self.messagelist[uid]['flags'] = imaputil.flagsimap2maildir(flags)