Using Exchange Activesync if a calendar entry becomes corrupt it can cause Outlook to crash shortly after opening the mailbox. Essentially Outlook tries to sync the calendar items and fails at the corrupt entry, crashes and restarts. In the event log this will show as a Error 1000 and may reference pstprx32.dll as the failing module.
The local OST file for the use is irrevocably corrupted at this point, but since it is only an offline cache of data it can be rebuilt.
Step 1: Close Outlook
Step 2: Navigate to the user's OST file and delete it. This file, depending on the version of outlook, may be in the users documents folder or in their hidden appdata folder.
Now go find and repair the corrupted calendar entry.
Step 3: Open smartermail web client and login
Step 4: Go to the calendar and view all appointments
Step 5: Sort the appointments by end date and look for an end date that is outside of the normal scope, usually from before the start date.
Step 6: Set a reasonable end date, or simply delete that calendar entry
Step 7: Open Outlook on their machine to regenerate the OST file