I was hit with a nice error when attempting to mount several Exchange databases on my new Exchange 2010 SP2 server that I had setup in a lab envionment for production testing.

The error:

——————————————————–Microsoft Exchange Error——————————————————–
Failed to mount database ‘IJ’.IJFailedError:Couldn’t mount the database that you specified. Specified database: IJ; Error code: An Active Manager operation failed. Error The database action failed. Error: Operation failed with message: MapiExceptionTooManyMountedDatabases: Unable to mount database. (hr=0x8004060e, ec=-2147219954). [Database: IJ, Server: EXCHANGE.JERMSMIT.LOCAL].An Active Manager operation failed. Error The database action failed. Error: Operation failed with message: MapiExceptionTooManyMountedDatabases: Unable to mount database. (hr=0x8004060e, ec=-2147219954). [Database: IJ, Server: EXCHANGE.JERMSMIT.LOCAL]An Active Manager operation failed. Error Operation failed with message: MapiExceptionTooManyMountedDatabases: Unable to mount database. (hr=0x8004060e, ec=-2147219954). [Server: EXCHANGE.JERMSMIT.LOCAL]MapiExceptionTooManyMountedDatabases: Unable to mount database. (hr=0x8004060e, ec=-2147219954)
——————————————————–OK——————————————————–

The cause of this issue is because Unlicensed (trial) of Exchange 2010 servers are limited to 5 databases. In the Application event log I noticed the following message:

Event ID: 9591 – Exceeded the max number of 5 MDBs on this server.

It seems I have exceeded the number of databases that can be mounted during my trail. I will now apply a MSDN license and see how things work out.