I got a problem on all mail boxes using imap (mostly outlook clients, but some webmail only). Basically, all imap users lost access to their imap subscriptions in outlook. At least one rule added via webmail had to be redone. This is a multiserver setup with separate mail servers. I added one more server and forced a mailbox resync to propagate the settings and mailbox information to the new server. Other than that, I upgraded ispconfig on all servers, beforehand. I'm not sure what caused the problem and where outlook keeps its own subsciptions. EDIT: Looks like the file for subscriptions is /Maildir/subscriptions Is it possible that a Mail resync via the tools menu in the web interface deletes or regenerates this file ? Any hints?