Database 'ChangeAuditor' is already open and can only have one user at a time (4255599)

The Coordinator log states the following after initial installation ChangeAuditor:

ERROR: Database 'ChangeAuditor' is already open and can only have one user at a time.

Cause 1 - Another connection is open via Management Studio.

Cause 2 - The Change Auditor database was created manually.

Cause 3 - The Change Auditor database is in single user mode.

Resolution 1

Running "sp_who" from a new query window should show the process id, database and user responsible.

You can then run "KILL <session id> to terminate the connection.

Resolution 2

The ChangeAuditor database needs to be created by the Coordinator, this ensures the roles and permissions are setup correctly.

Delete the new ChangeAuditor database and start the Coordinator which will create the database.

Resolution 3

The ChangeAuditor database is in Single user mode (sometimes get stuck during an upgrade) and needs to be put back into multi-user mode.

In properties of the ChangeAuditor database | "Options" page | "State" | change the "Restrict Access" setting to "MULTI_USER".

Resolution 4

An Agent, Coordinator, or other connection still has a handle on the ChangeAuditor database even though Resolution 1 returns no spid's with connections.

1. (for SQL 2008 or newer) Check and record the file permissions on the ChangeAuditor database mdf and ldf files.
2. Detach the ChangeAuditor database from SQL.
3. Close the SQL Management Studio.
4. After a minute, open SQL Management Studio and Re-Attach the ChangeAuditor database. (If SQL 2008 or newer, you will need to re-set the file permissions on the mdf and ldf files.)

Resolution 5