I have several users that are using Outlook 2011 for Mac and connecting to our Exchange 2010 server. It doesn't matter to me which client they use, however we have had several instances of users exporting their entire mailbox into a .OLM file, and their messages being removed from the Exchange server. Once they do this, reimporting the messages seems to leave them in a corrupt state. They appear correctly within Outlook for Mac, but when you try to access the messages via OWA or Outlook 2003 (Haven't tested other versions of Outlook), you get an error message:
This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible.
Obviously I can restore everything from backup and the user is back up and running. I have advised the users to stop using Outlook for Mac, and they are perfectly happy with OWA. However, I would like to prevent this from happening again. My initial thought was to prevent Outlook 2011 for Mac clients from connecting to my Exchange server. I found this TechNet article, but I believe Outlook 2010 and 2011 are both version 14. I definitely don't want to block my Outlook 2010 users!
So, I have 2 questions:
- Is there a less drastic way to prevent this problem? (Or to fix it once it has happened?)
- Is there a way to block these specific clients from connecting to my Exchange server?