Windows Image Backup Server Error 0X807800C5
Problem :Windows Image Backup is failing while backing up a drive. In my case, it was a "bare metal" backup scenario. You may also find the following error in the "Event Viewer" under "Applications and Services Log, Microsoft, Windows, Backup"
"The backup operation that started at '2014-05-13T16:49:41.618242900Z' has failed with following error code '0x807800C5'
(There was a failure in preparing the backup image of one of the volumes in the backup set.). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved."
Description;I think this is happening because of the VSS function. I couldn't find anything official but I have a feeling that when the backup tries to create a snapshot of the volume, it doesn't have enough allocated space on the drive to create the full snapshot. After a couple of blogs on the web, I cross people suggesting to shrink the drive and leave around 10GB of unallocated space.
So if you already have the full space "allocated" to the volume, your problem might just be that. You need to have a little bit of unallocated space.
Solution;Go to "Computer Management, Storage, Disk Management" right click on the volume you want to shrink and choose "Shrink Volume". Decide how much you want to shrink the disk and apply. Be careful! Make sure you have a backup of the volume or data before you proceed with this procedure as during this process you might loose data!!! (Did it ever happened to me before?? Never! But I would rather warn you!)
A second place to look is the "limit" of the shadow copies. Right click on one of your drives in "Windows Explorer" and click on "Configure Shadow Copies". Choose the disk you want to activate the "shadow copies" and click on "settings". Check the option "No Limit". I don't know what difference this makes for the Windows Image Backup but in my case, this little option was the problem. Unfortunately, I had to dedicate a full disk for this purpose because I didn't want to make a full disk with the "No Limit" option. Have a look at these conversations at TechNet Forums for details;
Note: This procedure worked like a charm under a Windows Server 2012 R2 but it is also applicable to Windows 7, 8, 8.1 or Server 2008, 2008R2...