Server is Novell Groupwise. After a while, this error Select failed, server replied: A001162 NO SELECT ( 8908 ) pops up, and keeps coming every second or so. Only way to stop it is to restart akonadi. This may obviously be some server-side error, however it's not handled really gracefully in the client... especially if you come back to the office in the morning, the notification system has a few thousand messages for you and still keeps making a noise every second. :) Reproducible: Sometimes Steps to Reproduce: 1. Run Akonadi server with IMAP resource on Novell Groupwise 2. Wait
The IMAP resource has a new maintainer, reassigning to him.
If this still applies to >= 4.11.3, can you check your .xession-errors for some debug info what the imap resource is doing? You may have to enable the debug info first using kdebugdialog.
In the meantime I put up some efforts to figure out what happens. Result: This was caused by a bug in Novell Groupwise, which for mysterious reasons starts sending negative (!) UUIDS. Hilarity ensues. Not much we can do here, setting invalid.