Can't mount mailbox database


After replacing a harddisk and copying my Exchange database files I cannot mount them. Before copying them I stopped the Exchange Storage service so my databases are clean. But when I try to mount them I get the error MapiExceptionCallFailed: Unable to mount database. (hr=0x80004005, ec=-546)

I already tried several things (including various eseutil runs) but the error persists.

I also tried to restore a backup of the database (using Windows Server Backup). After the restore I got the error "Unable to read the log file header. Error -546"

asked on Server Fault Jan 6, 2017 by Martin Walter • edited Jan 6, 2017 by Martin Walter

1 Answer


The problem seems to be a different size for the new disk. The old disk (4TB) was likely emulating 512 bytes sectors while the new disk (RAID10) is 2048 bytes sectors. I did try to store the database on an old 2TB drive but that was real 512 bytes sectors so the error persistet.

After reading I just moved all log files to another folder and was then able to mount the databases.

Now I could see the mails in the folder view but all mails were reported as missing. I ran isinteg.exe and it fixed a lot of errors. After that everything seems to be ok, I'm only missing a couple of mails from the last days.

answered on Server Fault Jan 7, 2017 by Martin Walter • edited Dec 17, 2020 by Eric Simson

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