--- a/artemis.py	Mon Nov 15 10:39:40 2010 -0800
+++ b/artemis.py	Mon Nov 15 10:46:46 2010 -0800
@@ -60,6 +60,7 @@
     for issue in issues:
         mbox = mailbox.Maildir(issue, factory=mailbox.MaildirMessage)
         root = _find_root_key(mbox)
+        if not root: continue
         property_match = True
         for property,value in properties:
             if value: