[Dovecot] dovecot 1.1.6 and outloook express 6 out of sync

[gyre]

Apologies if this has been discussed before.

I have dovecot 1.1.6 installed on my qnap NAS.  I connect to the imap server 
using outlook express 6 on my XP sp3 box.

I notice, after a time, that what I see in outlook express isn't what is 
actually on the imap server.

For example, in one of my folders, many messages are missing.  On another, 
headers of messages start getting duplicated and the bodies don't always 
match the headers.

If I tell outlook express to clean up and reset... i.e. remove all the 
headers and bodies so they get downloaded again, then everything appears 
again... for a little while.

Likewise, if I delete all the index files on the server and restart it, all 
seems well for a bit.

Somehow, OE is getting out of sync with the imap server.

This same OE client is also talking to other non-dovecot imap servers and I 
don't see this out-of-sync-ness or corruption at all.

I realise this is a vaguely stated problem, but I'm not a imap person and 
dont yet know how to narrow it down further, nor can I reliably recreate it.

Has anybody seen anything like this before?

Thanks.

-- gyre --