This issue started about a week ago. If I ignore all the known issues with Outlook 2011 since moving to Mountain Lion, I would say Outlook has been running fine until last week. I couldn't see anything on the forum that was similar to my issue. I have also posted this to the Apple support forum.

Here's my computers info:

• OS X (10.8.2(
• Processor: 3.1 GHZ Intel Core i5
• Mem: 12 GB 1333 MHZ DDR3
• Office 2011 Version 14.2.5

Here's the issue:

My work email is set up in Outlook 2011 version 14.2.5 using IMAP. I go through my day as usual reading emails, responding to them, and filing them away in folders (on the server). I can go through 100 emails in my inbox to only 10 by the end of the day, all have been read. Emails that are no longer in my inbox have been either read, responded to, filled away and/or deleted. I am able to receive and send emails with no errors. However, once I leave work and view my emails online or on another program (such as MacMail), I see those 100 emails still in my inbox! I see no pattern to it either. (The most recent email in a conversation has been marked as read but several earlier ones were not).

The strangest part: All those emails I filed away in folders on the server or deleted are in those folders AND in my inbox. Therefore, if I refile the emails, or delete them I will have duplicate emails in those folders. I've tried repairing the folder but that only put the server inbox back into my outlook but I still can't make any changes that show on the Webmail. We've also rebuilt the identity and that didn't do anything.

If I make any changes in Mail (On a different computer that is on Snow Leopard) or on the web, I just sync Outlook and it shows the changes in Outlook but it won't show any of my Outlook changes in the webmail.

Essentially this is the syncing issue: 

Other programs --> Server --> Outlook = OK

Server --> Outlook = OK

Outlook -x-> Server = NOT OK

I'd like to reiterate that this started last Tuesday (Nov 20) and I can still receive and send emails just fine and no email has been lost.  Our IT can't figure it out.