KeyError during IMAP to IMAP sync of deleted msgs

Dan Christensen jdc at
Tue Dec 8 15:36:17 GMT 2009

Dan Christensen <jdc at> writes:

> Dan Christensen <jdc at> writes:
>> Unfortunately, the problem is more serious than having to restart
>> offlineimap.  After the sync finally completed, one message was missing
>> from the local IMAP folder, and 55 messages were duplicated!
> Tried from scratch again, and one message went missing and 29 were
> duplicated.  Also lost a read mark.  The folder I'm trying to sync
> has about 6000 new messages at the local end, and 0 at the remote
> end.

Sorry, I take it back:  the missing message was due to a problem in
populating the imap group in the first place, before initiating the
sync.  But the duplicated messages (and the keyerrors during sync)
appear to be bugs in offlineimap.

I tried the whole process another time, first populating the remote imap
server with the 6000 messages, and using offlineimap to copy them to the
local server.  This time there were no problems at all.  Unfortunately,
this method causes double the network traffic.

Summary:  it appears that there's a bug involving copying many messages
from a local imap server to a remote one.

This is now Issue #193 on trac:

where I have provided logs and also figured out that the problem occurs
more often with maxconnections set higher.


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