Topic Last Modified: 2008-02-20

The Microsoft Exchange Database Troubleshooter Tool detected one or more MSExchangeIS 9519 events with error code 0x89a in the Application log. The event indicates that the database specified could not be mounted because the Exchange organization has more than one domain and one or more well known security identifiers is included in the access control list (ACL) for the database.


This problem occurs if the following conditions are true:

  • The security descriptor of a database object is modified to include a well-known user or a well-known group.

  • More than one domain exists in the forest.

This problem may also occur if a security identifier (SID) in the database object has conflicting values with another object in the Active Directory directory service for one of the following attributes:

  • objectSID

  • msExchMasterAccountSid

  • SIDHistory

These attributes must be unique in the forest.

User Action

To resolve the issue for Exchange Server 2003, follow the guidance in the following Microsoft Knowledge Base articles:

To resolve the issue for Exchange Server 2007, install Exchange Server 2007 Service Pack 1 (SP1) from the Exchange Server 2007 Downloads page (