Outook 2007: Cannot delete e-mail / Crashes when you try to open

Hello, I was hoping someone could help me with an Outlook 2007 issue a user has been having. Last week, our exchange server was flooded by a lot of e-mails, causing our users messages they tried to send out to fail and given a Outlook delivery delayed message for each. The issue was solved but I have one user who still has a delivery delayed mail in this inbox and upon trying to open it, Outlook crashes and if you try to deleted it, you get the message:

"One or more items in the folder you synchronized do not match. To resolve the conflicts, open the items, and they try this operation again."

I was thinking this notification was in sync with the e-mail that was delayed, so I did a search and couldn't not find anything related to it. Any ideas on who to get rid of this troublesome message?

I figured it out. I asked the user to log into OWA and try to delete it from there. Sure enough, it worked and the e-mail is longer giving him a problem.

Thank you for you help, though!