I have to add: this time my above mentioned workaround does not work. The culprit seems to be akonadi 1.7.2-1. Downgrading to akonadi 1.6.2-2 solved the problem here. The downgrade is a bit awkward (using snapshot.debian.org) but it works. Unfortunatelly I cannot provide any debug informations but reassigning the bug to akonadi seems to be appropriate. Regards Markus Huber