A Windows SBS 2011 server at one of our customers locations installed several updates last evening, and when they came into work this morning they discovered they were not receiving any email. Neither was the remote web workplace or OWA working. After some digging around I noticed the following error in the event log.The Module DLL C:\Program Files\Microsoft\Exchange Server\V14\ClientAccess\Owa\auth\exppw.dll failed to load.
I tried a number of solutions that I found online, but none of them worked. Somewhere though I saw a tip that mentioned downloading Exchange 2010 SP3 and doing a reinstall of the Service Pack. Sure enough, I noticed that one of the updates that was installed last night was Exchange 2010 Service Pack 3. I downloaded the SP from Microsoft’s servers and reinstalled it. This fixed the above problems immediately.