Outlook issues when msExchMasterAccountSID attribute exists on a user account

S’applique à : Outlook 2016Outlook 2013Microsoft Outlook 2010


After a mailbox move or migration, one or more of the following issues may be exhibited:
  • Some mailboxes show as linked or shared rather than as user mailboxes.
  • Repeated mailbox credential prompts in Microsoft Outlook or Outlook Web App (OWA)
  • Unexpected delays in, or halted mail flow.
  • Problems accessing Public Folders, sometimes resulting in the following error:

    Cannot expand the folder. Microsoft Exchange is not available. Either there are network problems or the Exchange Server is down for maintenance.


This behavior can occur if a regular user account has the msExchMasterAccountSID attribute populated in Active Directory.


To correct this issue, run the following Powershell command from the Exchange Management Shell:

Set-User -Identity useraddress -LinkedMasterAccount $null

For example:

Set-User -Identity user@fabricam.com -LinkedMasterAccount $null

This will remove the msExchMasterAccountSID attribute from the user’s account.

More Information

The msExchMasterAccountSID attribute should not exist for a regular user account in Active Directory. A regular user will be identified as having an msExchRecipientTypeDetails attribute value of 1 (1 = normal mailbox, 2 = linked mailbox.)

If msExchRecipientTypeDetails = 1, then msExchMasterAccountSID should not exist on the account in Active Directory.

For more information on possible values for the msExchRecipientTypeDetails attribute, see the following Office 365 blog post:

O365: Exchange and AD - How msExchRecipientDisplayType and msExchangeRecipientTypeDetails Relate to Your On-Premises