Fehlercode: MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005, ec=-501)
Well this happens to me and I was able to resolve it by restoring it from backup and then mount. It works!
There could be the following causes for this erroneous situation:
* The ‘DomainNameExchange Servers’ group is not assigned the ‘Manage auditing and security log’ user right.
* The Exchange server database file is corrupt or damaged.
For the first cause, check this solution:http://kbalertz.com/925825/Event-logged-Application-mount-database-Exchange-Server.aspx
If this doesn’t solve the problem you will have to restore it from an old backup file or run eseutil.exe command utility. Please follow these steps:
1. Run Eseutil /p, a hard repair process on the corrupted database.
2. Run Eseutil /d, to defragment the database. Offline defragmentation process makes a new physical database
3. Now run Isinteg -fix to Check the consistency of the Exchange server database. You may need to run Isinteg several times until it returns zero errors.
Note: Eseutil /p may cause data loss as it removes the damaged database pages during repair process to bring the database file into consistent state.