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Problems with OWA and ActiveSync after Update Rollups on Exchange 2010 SP1

Last Modified: 2013-03-27
So, my Windows Update applied Update Rollups 7-v2 and 8 for Exchange 2010 SP1 and now both OWA and ActiveSync are no longer working. The error I receive when I try to go to OWA is this:

Could not load file or assembly '2013-03-12 21-00 Copy of Microsoft.Exchange.Clients.Owa' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I have tried removing the updates, re-applying them as well as resetting and re-configuring the virtual directories all to no avail. Short of restoring the system to a point before the update, can anyone make another suggestion?

Let me know. Thanks!
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New Updates ruined some files..

Restoring from backup is the only option left.. as u have already resetted VD's & all other possible ways.

I have seen in some articles that we have to re-install CAS role from Command prompt.

Check the similar issue happened on 2007 server.

But restoring from backup would be ideal way.
AmitIT Architect
Distinguished Expert 2017

Most Valuable Expert 2014

I would skip SP2 and go straight to Exchange 2010 SP3. SP1 is very old. Even rollup 3 has suggested above is old.

The Exchange service packs effectively reinstall the entire product and will resolve a lot of issues.



Installed Service Pack. No dice. Uninstalled Client Access Services. No dice. Anymore ideas?
Most Valuable Expert 2014

You are getting the identical error after the service pack installation? Highly unusual to survive a service pack installation.



Yes, same error after SP3 install. Any other ideas ?
Most Valuable Expert 2014

My instinct is that something else must have installed at the same time, or around the same time as the updates that you installed for Exchange. That has broken things. .netframework would be my guess. I am finding nothing specifically related to Exchange, it is all developer related, which points to something else. As I wrote above, highly unusual for errors to survive a reinstall, which points to something outside of Exchange as the cause.

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The issue was one that I was able to fix on my own. None of the other answers given seemed to relate to the fix directly.

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