I recently started to get this when backing up a users computer. This is just a stardard PC backup.
This is just a sample of a list of similar errors i get.
Job ended: Friday, August 28, 2015 at 3:01:42 PM Completed status: Failed Final error: 0xe0008488 - Access is denied. Final error category: Security Errors For additional information regarding this error refer to link V-79-57344-33928
V-79-57344-33928 - Access is denied. Access denied to file $Windows.~BT\Sources\SafeOS\SafeOS.Mount\Windows\INF\mshdc.inf. The item \\user-computer\C:\$Windows.~BT\Sources\SafeOS\SafeOS.Mount\Windows\INF\mshdc.inf in use - ...V-79-57344-33928 - Access is denied.
If you are using a compatible OS, then -
1) Enable Advanced Open File option and set it to use the MS VSS provider.
2) If running any AV scans, set it to exclude from scanning the BE processes.
3) Uncheck the option to backup mountpoints and symbolic links.