I have a user with an appointment on her calendar that seems to be corrupted. When she tries to open it, she gets the message "Can't open this item. Unknown error." When she tries to delete it, she gets the message "Unknown error." It's also preventing her Palm from being able to synchronize it's calendar with Outlook. It fails at that entry. I've tried rebooting, re-accepting the original meeting notice, etc. Nothing seems to help. I have even tried another machine, but still couldn't delete it or open it. Thanks in advance for suggestions.