After updating today, kmail refuses to start reporting "Akonadi personal information service is not operational". The listed errors were several log errors but the most important seems "Akonadi control process not registered at D-bus". Any suggestions to fix the problem? This problem also affects the calendar as well.

This might be a similar issue as was run into during testing and is mysql related.

Try running "akonaditray", then click system-tray expand icon > right click akonaditray > configure > hit start

That will probably show a mysql/iotop error log, if you switch database storage driver to SQLite in the "akonadi server configuration" tab, it will probably work to start akonadi.

Backing up the old mysql database, deleting the current, and switch back to Mysql and let it rebuild the database is the best solution found so far. Not clear yet were the corruption in the database comes from yet.

Ran akonaditray as instructed and switched to SQLite. It started the akonadi server and rebuilt the database. Kmail seems to be working. However, I should probably switch back to mysql as it is the default. What is the file name for the old mysql database, or current one and where is it located. I scanned through .local and .kde4 but could not find anything.

I found the file and removed it. Akonadi is now running with mysql. Something I noticed, the new directory has a different name than the previous one. I wonder if the new directory name change is causing the problem. Thanks demm for your quick reply and your excellent distro.