After today's KDE Neon update from Akonadi 4:16.08.2+p16.04+git20161117.2007-0 to 4:16.08.3+p16.04+git20161208.0216-0, Archive Mail Agent spins at 100% CPU.
It starts doing this immediately after login and also continues immediately after an "akonadictl restart".
Upon "akonadictl stop", Archive Mail Agent crashes instead of shutting down cleanly.
In Akonadi console, this Agent is never displayed as running or online, but labeled with an unconnected plug icon and shown as offline. Meanwhile, it's happily spinning away, eating CPU and causing lots of noise due to the CPU fan having to run at full speed...
The only workaround I could find so far was entirely removing this Akonadi Agent using the Akonadi console. I'm not sure what effects this might have, however...
What option's do I have to determine why this agent is not initialising correctly but (apparently) enters an infinite loop instead? What's it doing?
Related to bug 373443, appears to be fixed on master and branch head.
*** This bug has been marked as a duplicate of bug 373443 ***