I am running Scalix 11.3 with 50GB data for about 1.5 year now (just updated from 11.0.2). 70% of the clients are Thunderbird, one or two people MS Outlook with occasional 4-5 more just for calendar or contacts. The rest is using SWA.
Two accounts out of 20 suffer from IMAP locking issue. They mostly use Thunderbird/IMAP (Windows XP) but do have MS outlook profile setup though rarely utilize it. Frequently, they connect from office and home, and while on the road. One of them is about 2.2 GB big, other is closer to 1GB.
Once in 2-3 days, the account get locked, meaning they start Thunderbird and "cannot SELECT that folder" message appears. They cannot download new messages or see old ones. The only way to remedy the problem is to kill all their sessions and remove the imap-cache.
As always, any input will help.
Thanks