Sicnce the new bulk-updating code went in, approximately once a day I experience a hand in Kontact where it can (usually) list all the mails in a folder and all the folders, and the address book will list all the contact names in the address book, but clicking on an email or a contact will not load the relevant email or contact card in the viewer.

When this happens, trying to delete an email also returns an error about my IMAP account not having an associated trash folder. This is odd as I do not have IMAP set up :) see below:

My setup is as follows:

* POP3 server for incoming mail
* A couple dozen local mail filters, all of which match on to/cc/bcc (and for some also the subject) and send incoming email into folders
* Local maildir storage in the default location

When this happens, I can exit Kontact, shut down akaondi, remove ~/.config/akonadi/agent_config_akonadi_maildir_resource_0_changes.dat and then start everything up again and it once again functions correctly.

When hung, the maildir resource is simply waiting quietly in its event loop. It is not stuck in a loop anywhere nor is it hung on a blocking call.

Using akonadiconsole, requests for emails simply go unanswered with no apparent debug output in the debut panel (though I do get debug output for listing the folders themselves, incoming email over pop3, filtering, etc)

Attached is an example .dat file which was on disk at the time of a breakage.

Reproducible: Sometimes