I have one user who has some problem with her Calendar. in OWA, she'll go to the calendar and click on Share... -- to share it with a coworker. The usual window opens asking for the recipient, subject, and the type of sharing requested (free/busy only, All Information, etc).
When she clicks on send, the top of the window turns red and says "The item can't be opened because it's become corrupted". On mouseover, I see a more specific error message "The security principal specified is already on the permission set"
Can't seem to figure out what to do with this..
See attachment for screenshots.
This is Exchange 2010 SP2 Rollup 4v2