Windows 10 backup error code 0x807800C5

I'm running a Lenovo T450s, Win 10 Home 64-bit. All hardware drivers, operating system, and software on the machine are 100% up to date. I also have a Buffalo LS421DE50E NAS enclosure populated with 2 Toshiba 3 TB hard drives in a RAID1 array which has 838.4 GB in use. The firmware is current.

This array is used a LOT and is functioning flawlessly with the exception of creating
backups. I did run a File History backup last evening to the Array and it completed without incident which puzzled me given the behavior below.

But every time I try and do a System Image Backup from the File History panel OR try to run a Scheduled backup with Backup and Restore (Windows 7), they fail saying:

"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

I have tried both File Hist and Backup methods several times with the same results. I can add, delete, modify files in the Array no problem.

The Array is defined as part of my workgroup.

The software does know the Array is online as it displays the "Green" icon and shows the used vs total space.

Any ideas?

Steve

dalchina said:

Windows Backup failed with error 0x807800C5 - Super User

Hi, possibly see Workaround there. It sounds a similar situation to yours.

Thanks! I'll head over there. Didn't see the thread - sorry.

See if this link is useful: windows 8 backup error code 0x807800C5 - Microsoft Community

Popped over there but didn't help. I don't use windows defender. I am the SU of the system. File backup works fine through the same software so it doesn't seem to be a permission issue. The software doesn't recognize my NAS as a hard drive, only as network storage. I've rebooted, TOTALLY cleaned out the target directory and started over, no dice.

Could this be a size issue: Server 2012 wbadmin backup failing - The mounted backup volume is inaccessible

zbook said:

See if this link is useful: windows 8 backup error code 0x807800C5 - Microsoft Community

Thank. Totally wiping out the target directory, again.... And one SUQ (Stupid User Question. ) can I run sfc /scannow on a Raid1 array?

zbook said:

Could this be a size issue: Server 2012 wbadmin backup failing - The mounted backup volume is inaccessible

Thanks, but I kind of doubt it. 2 TB of free space, one partition, shouldn't be any issue. I thought maybe the directory pointer was whacked so I removed the directory and created a totally new one. No luck. I think I may need to look into some better software for backups than M$ supplies. Shouldn't be necessary but at this point, it would seem it is.

Thanks, I'll look into it 'cause winblows sux... I'd be back to linux in a heartbeat but I support too many on winblows so have to stay current.