I ran into this strange error with Exchange Server 2010 today.
Error code: An Active Manager
operation failed. Error: The database action failed. Error: Operation
with message: MapiExceptionNotFound: Unable to mount database.
We are trying to add an extra mailbox database to our existing Exchange 2010 DAG. Disk spaces (SAN) has also been assigned to this server. So we are good with spaces. Every time when we try to mount the new mailbox database, it is giving us the above error.
Searching online, we found that this is a known issue with Microsoft Exchange Server.
According to Microsoft, a preferred Domain Controller needs to set on Exchange.
Another way of doing this is by using EMC.
1 – Launch EMC
2 – Right-click on “Organization Configuration” and choose “Modify Configuration Domain Controller”
3 – Select your preferred domain and DC
4 – Do the same under “Recipient Configuration” and choose “Modify Recipient Scope”
5 – Select the same DC from step 3
6 – Close and relaunch EMC