Challenge
The number of databases that can be mounted in Veeam Explorer for Exchange at a time is currently limited to 15.
Solution
If the limit has been reached, you will not be able to mount new databases. You can manually remove unnecessary mailbox stores in Veeam Explorer for Exchange and then add the store from which you want to restore items.
More Information
If you have any questions or problems, please contact Veeam Support at http://www.veeam.com/support