Hi again, I found two workarounds for this bug: 1) a change of the filter type: copying mails to subdirs instead of moving (INBOX has to be cleaned manually) 2) adding a placeholder mail in INBOX that is not filtered/moved away The bug seems to occur only, when INBOX is empty in the local copy and the filters move *all* mails from INBOX to other directories when syncing. Thanks in advance for your help. Cheers, Christian