--- a/server/python/junius/proto/imap.py
+++ b/server/python/junius/proto/imap.py
@@ -209,17 +209,16 @@ class ImapClientFactory(protocol.ClientF
 # 'raw/message/rfc822' as output
 class IMAPConverter(base.ConverterBase):
   def convert(self, doc):
     # I need the binary attachment.
     return self.doc_model.open_attachment(doc['_id'], "rfc822",
               ).addCallback(self._cb_got_attachment, doc)
 
   def _cb_got_attachment(self, content, doc):
-    assert content, "can't locate attachment for %r" % doc['_id']
     # the 'rfc822' module knows what to do...
     return doc_from_bytes(content)
 
 
 class IMAPAccount(base.AccountBase):
   def startSync(self, conductor):
     self.factory = ImapClientFactory(self, conductor)
     return self.factory.connect()