If you have users with issues involving their calendars, Microsoft has a special utility to help resolve problems. The Calendar Checking Tool for Outlook (CalCheck) can be used when there are known problems, or can be executed to run and find potential problems.
CalCheck is not an offline tool, meaning it's not intended to be run on locally stored, PST calendars, but instead it's meant to be run against calendars that reside on Exchange servers (OST). To clarify, it's meant to be run locally on a local copy of Outlook (versions 2007-2013), but only when connected to an Exchange server (versions 2003-2013). It does not work with accounts for IMAP, POP3, or any other non-Exchange mail servers.
CalCheck is a command-line utility that opens an Outlook profile and then opens the calendar component. When run, it checks for the following things:
Verifies each calendar entry
- Checks permissions
- Looks for missing entries
- Sorts out free/busy items
- Identifies problems with auto booking
Once the utility completes its scan, CalCheck.log and CalCheckErr.csv files are created to show potential problems and/or items to fix or remove as well as processing information.
Using the command-line options, the tool can be automated somewhat, reading a text file list of mailboxes and working through each one.
Download: Calendar Checking Tool for Outlook
Here's the list of command-line options: