Exchange 2010 unmount database repair procedure:
Command to soft repair the Exchange EDB (database file)
# eseutil /mh .\exchange1.edb
Command to hard repair edb file
# eseutil /m /l /d .\exchange1.edb
full content of above site:
Resolve Exchange 2010 Error Unable to Mount Database
To deal with this Exchange 2010 issue: unable to mount the database, it is important to first understand the role of Transaction logs.
A transaction log is the life-and-blood for an Exchange Server, helping it retain smooth functioning on the server. Each and every transaction made to the server is being written in these log files, which are then committed to the database. Until the transaction is not saved in the database, it remains the system memory and the transaction logs.
If any crash occurs during this event, then you lose the content from the memory during the reboot, because it was not completely saved on to the exchange database files. This is why, transaction logs are the robust recovery mechanism to safely restore the data to an Exchange database in a consistent state.
This below mentioned error message is displayed in Exchange 2010, when you are unable to mount a database from a backup:
Exchange is unable to mount the database that you specified. Specified database: d1cdba46-6f79-46f2- ba14-3ae2fa8aad43; Error code: MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005,ec=-2147467259)
CAUSE OF THE ERROR:
Microsoft has provided Eseutil utility to verify whether or not the database is in clean shutdown state. If isn’t in a clean shutdown state, then this inbuilt utility may help you to fix up the issues and bring the database into consistency. And if the data is in consistent state, then using the below mentioned resolution, you can restore the data successfully from the backup.
Removal of log file is one of the common reasons, due to which the database may fail to mount. To resolve the issues, it is important to first perform a consistency check.
Verify and Repair Inconsistent Database Using Soft Repair
Eseutil tool can be of great help in performing soft recovery. This method is useful to re-mount database after an abrupt stop.
The user will now be able to mount the database successfully. However, if not then verify the consistency of transaction logs.
Verify and Repair Database Logs Using Hard Repair
Eseutil tool is even helpful in performing hard repair recovery to test the database for any damaged pages. If there are any, then the tool will delete them. This recovery method uses Restore mode (/c) in Eseutil tool to mount a database from online backup.
However, if you are still unable to mount the database, then try using a reliable third-party Exchange Server Recovery tool to efficiently restore data in any condition of damage – even where Eseutil tool fails to deliver the desired result. Kernel for Exchange Server is an advanced recovery tool to repair corrupt Exchange database files, without requiring log files or Exchange services. EDB to PST converter tool even allows you to restore EDB files directly to live Exchange Server and to Office 365 mailbox.