I’ve had this problem on a couple of machines now, both were running Outlook 2007 SP3. Outlook appears to be working normally, but if you try to access the calender it just hangs and displays “not responding” in the title bar.
Eventually you are left with no choice but to close and restart Outlook. There seems to be several problems with this, and therefore several possible solutions.
Outlook 2007 Hangs when accessing the Calendar – useful command line switches
First, try the easy solution of starting Outlook with some command line switches, this procedure seemed to help on both machines but only fixed it on one. I used:
outlook /resettodobar /cleanprofile /cleanviews /cleandmrecords /cleanfreebusy
There are lots of command line options that you can apply to Outlook and they are all explained here:
Access to the calender in Outlook 2007 may be blocked by some existing tasks
It seems that the default calendar view also shows the task list, and I found the tasks to be where the problem originated from, and in both cases the tasks were incomplete and not correctly filled out.
Go into the tasks tab and list your outstanding tasks, you may see some entries that are entirely blank, you may be unable to click on them or access them at all, like this:
Not only was I unable to click on these tasks, but they were constantly refreshing like they could not be properly found.
Try changing the view so that you can get a more stable look at the remaining tasks:
By changing the view I was able to get a stable view of the remaining tasks. Deleting the rogue tasks, which were flagged as incomplete, but many years old solved the issue. The calendar became accessible again.
I spent quite a long time trying various fixes to this quite basic fault in Outlook, quite a few others have experienced almost the same problem as me, so hopefully this saves someone else some time.