Hello,
I have on-premise Exchange 2013 CU21 (single server hosting both the mailbox and cas role) that is setup in hybrid mode with Exchange Online using ADFS/AADConnect; running on Windows 2012 R2.
I noticed that the Exchange Mailbox Assistants (MSExchangeMailboxAssistants.exe) crashes every 5 minutes.
Error,10/27/2018 8:47:28 PM,Service Control Manager,7031,None,The Microsoft Exchange Mailbox Assistants service terminated unexpectedly. It has done this 1 time(s). The following corrective action will be taken in 5000 milliseconds: Restart the service.
Error,10/27/2018 8:47:27 PM,MSExchange Common,4999,General,"Watson report about to be sent for process id: 48196, with parameters: E12IIS, c-RTL-AMD64, 15.00.1395.004, MSExchangeMailboxAssistants, M.Exchange.WebServices, M.E.W.A.AutodiscoverRequest.InternalExecute, M.E.W.Autodiscover.AutodiscoverResponseException, bd31, 15.00.1395.000.
I have tried to:
- Migrate suspicious mailboxes from one db to another and dropping corrupt items
- Checked database for any corruption
- Re-ran the hybrid configuration wizard
- Updated to latest .NET (4.7.2), as of a few weeks ago it is officially supported
I have no idea what is causing the error, I opened a ticket with MS and I am being told to apply the CU21 update again (which is pretty much saying re-install Exchange).
While I am not opposed to the idea, it is more of a last resort after I have explored all options.
The only thing that happened around the same time that the service started crashing is that we upgraded Active Directory (Domain/Forest) from 2012 to 2016; so we decommissioned 2012R2 servers and deployed 2016 servers for the new DCs.
Exchange is tightly integrated with AD; so this service starts crashing after the upgrade seems odd.
AD replications is healthy and working.
I am stumped, the error registered in the log has no details to go on as to why the service crashes. I already tried enabling expert logging in exchange for the mailbox assistant service.
Anyone run into something like this?