I too am getting the "Moving calendars to server account" pane when I open iCal
I too am getting the "Moving calendars to server account" pane when I open iCal. All fixes I have read seem to involve turning iCal off an on and/or rebooting. I cannot touch iCal. All is grayed out in iCal and in iCloud system preferences. I am using 10.8.5 and iCal version ... Well, that is grayed out too. Waiting a really long time does not seem to help.
MacBook Air, OS X Mountain Lion (10.8.5)