Windows 8 error code 0x807800C5 during Windows 7 File Recovery backup

The following error appears if you try to include a system image in your backup using the Windows 7 File Recovery backup tool.


There was a failure in preparing the backup image of one of the volumes in the backup set.

Details: The mounted backup volume is inaccessible. Please retry the operation.

Error code: 0x807800C5

According to this forum

For Win 8 only: The Win 7 back up program included with win 8 does not support backing up a image file to any kind of NAS device (UNIX, Linux) . Internally the program gives an error that the NAS device has an incompatible sector mapping type. You can backup to a hard drive that is attached to a different windows machine and then back up that file to your NAS. Convoluted, but it works.

So, backing up a system image to a Samba share is out of the question. To work around this, disable the creation of a system image in your backup.

I haven’t tried backing up to an NTFS-formatted iSCSI LUN, which might work. If anyone has tried that, I’d be interested to know the results.


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  1. #1 by Christian Aichmair on August 17, 2013 - 5:17 am

    Hi !
    Backup to NAS from Windows 8 works ( at least to Synology DS1813+ ) IF :
    – disable SMB2 and large packets in Synology
    – edit smb.conf and ADD “strict allocate = yes” to all Shares !!!

    After that also Windows 2012 can backup to NAS !!

    Hope it helps,
    Christian Aichmair

  2. #2 by Borg on September 15, 2013 - 8:37 am

    I’ll done everything what i found/read for this issue 0x807800C5.
    Notthing will work.

    Backup went well when if you disable the Windows Recover/Backup Systemcope, EFI-systempartion, Windows RE tools.

    But you dont want to do that. Thats the recovery solution.

    So I’ll think this is a Windows/Lunix issue. Why, because on my Homeserver everything went well. Why leaving the Home server, my controller can’t support the 3TB disk i bought and i went out of disk space. So I’ll went to the NAS (Synology) Bad choice.

    Have you fixed this issue. So yeah. How.

    • #3 by Mike Beach on September 15, 2013 - 9:19 am

      I haven’t found a solution for this issue.

  3. #4 by Gilles on February 11, 2014 - 4:36 am


    This post just to say thank you to this site and particularly to Christian A. who solve my issue (WIn 8.1 image system backup on Synology 412+) with his comment.
    Just one note as I add to use syno admin account to reach the NAS from Windows. Another user account, even with admin credentials, was refused.
    Thanks again