Error when creating a new resource mailbox - mailbox created but some properties weren't saved - could not open Microsoft System Attendant

All, I just completed a migration from Exchange 2007 to Exchange 2013 CU9 on premises. It appears everything went well, mail is flowing, no errors in events logs, so I've uninstalled the old 2007 server. Everything is working except, I just tried to create a new room resource in ECP and get a warning stating:

"This mailbox was created successfully, but some properties weren't saved." "Cannot open mailbox <fullyDistinguishedName>/cn=Microsoft System Attendant."

i've searched and searched, but cannot find a clear answer to this. I only have one 2013 server with one mailbox database and it is mounted (obviously, everything else is working fine as I mentioned).

Has anyone else encountered this and been able to fix it?


  • Edited by in2jars Tuesday, August 04, 2015 7:10 PM
August 4th, 2015 7:10pm

Does this help?
https://social.technet.microsoft.com/Forums/exchange/en-US/977dbcf9-ebd6-4dad-84cd-cf496972a8ec/the-room-mailbox-was-created-successfully-but-some-properties-werent-saved?forum=exchange2010

Thanks for the reply unfortunately I didn't find the linked thread helpful in my situation. I can say I receive this error every time I create a room resource in the EAC (tried creating a few test rooms today) and all my DCs are operational.

One of the linked discussions in that thread mentioned running Clean-MailboxDatabase which is now Update-MailboxStoreState in 2013. I may give that a try.

Other threads I've come across have suggested the following:

  1. Make sure mailbox database hosting arbitration mailboxes is mounted - it is
  2. Enable Migration arbitration mailbox - it is

Any other ideas?


  • Edited by in2jars Wednesday, August 05, 2015 2:20 AM added quote
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August 5th, 2015 2:12am

One of the linked discussions in that thread mentioned running Clean-MailboxDatabase which is now Update-MailboxStoreState in 2013. I may give that a try.


Didn't seem to do anything unfortunately.

No one else has come across this problem?

August 5th, 2015 7:36pm

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