Windows Backup failed with error 0x807800C5 incorrect function

This is the same error number as similar post, but not the same details

This is on a Windows 10 machine trying to backup to a FreeNas network location. Part of the backup completes (user files) but fails at the image backup with incorrect function.

Has anybody found a way to correct this problem in windows 10?

2 Answers

This issue may be caused by Windows only allowing one system image to be backed up to NAS. Windows 10, unlike older versions, is incapable of overwriting or deleting the first system image, so causing the second image backup to fail.

If this is your case, you can resolve this issue by either:

1. Renaming the original backed up system image
   Gain access to the NAS shell and rename the original system image from __nas_backup_WindowsImageBackup_host-name to __nas_backup_WindowsImageBackup_host-name.bak.

2. Rename the backup folder
   Find the location of the WindowsImageBackup folder located on the NAS, say f:, then rename F:\WindowsImageBackup to WindowsImageBackup.old.

5

I was able to get some downtime with the Windows Machines and FreeNas and was not able to figure out what, if anything needed to be changed to prevent Windows from having this problem.

To get around the issue, I created a tiny Ubuntu Server VM Samba Share, mounted the FreeNas backup directory to that machine, and then shared that folder via Samba to the Windows machines. Windows backup now works as expected and is performant enough (~40GB initial full backup with system image over the network in 15min 11sec) for the clients needs.

Your Answer

Sign up or log in

Sign up using Google Sign up using Facebook Sign up using Email and Password Submit

Post as a guest

Post Your Answer Discard

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy