You have calendar tracking enabled. Run ZCOLogCtl.exe (start->run->ZCOLogCtl.exe) and uncheck 'enable calendar tracking'.
You can safely delete all those .msg files.
Our policy is that old connectors work with new servers (ie, people upgrade their servers first, the update the dekstops). Looking through the 5.0.11-5.0.15 fixes, I see a couple that depend on server updates. |