I've recently upgraded zimbra to 7.2.0 (from 6.0.16). It's a small server, just 2 mailboxes.

After the upgrade, which went smoothly, every now and then (once a day maybe) thunderbird complains about an operation on INBOX failing because aparently the folder is READ-ONLY. The operation can be message delete, set message read, etc.

Restarting thunderbird fixes the problem.

I've been unable to find any error in the log files, and i'm clueless.

Any suggestion on what may be happening here?

Julian J. M.