I have a user that loaded a PST into Outlook 2010. The PST file had several calendars, which were loaded to the user's calendars. He has since deleted the PST file as he no longer needed access to it. The calendars are stuck in his calendar list, and the 'Delete Calendar' option is greyed out. This wouldn't be a problem, but each time he newly opens Outlook and goes to his calendar, he's notified that the PST file cannot be found and is then prompted to select it. There were five calendars, so it's a bit annoying to go through ten dialogs. How could these calendars be removed from Outlook?
Can you restore the .pst? It needs unloading from outlook before just deleting it.
You can solve the errors rather easily - just remove the data links in 'Control Panel'/'Mail'/[Data Files]. Don't do this yet.
See if you have options to remove the calendars there (probably not - now would be a good time to backup/export the working PST+calendar) and do so.
If you can still expand the contents of the deleted .pst in the Navigation pane then goto the folder view and right click and delete the offending calendar. More than likely you won't have this option so just remove the data files from the Account window (as mentioned above).
If the calendars are still showing, do you have the option of unselecting them from the Calendar window?