When I try doing a system state backup of a DC to the NAS using Windows Server Backup, it'll work the first time, but on all sucessive runs it fails with the error "Error in deletion of [C:\System Volume Information\001.dat] while pruning the target VHD: Error [0x80070020] The process cannot access the file because it is being used by another process." If I delete the previous backup from the NAS, the next backup works, then all sucessive backups again have the problem.
The Windows Server is 2012 (not R2) & the ReadyNas is a 316 using firmware 6.5.1. The NAS is domain joined. I tried installing the SMB Plus app and setting the SMB version to 2.0; it made no difference.
Updating to 6.6.0 seems to have fixed the problem. After updating, I've only had one reoccurrence of the error. On that occasion, the VPN tunnel between the server and the NAS had either been down before a backup job started or went down in the middle of the job; once the tunnel was back up, backups gave the "Error [0x80070020] The process cannot access the file because it is being used by another process" error until the backup was completely deleted, after which it resumed functioning correctly.
I was to quick in saying that 6.6.0 solves the Windows Server Backup to RN316 problem I was having. Prior to 6.6.0 every backup after the first would fail. With 6.6.0, backups after the initial work about 2/3 - 3/4 of the time. The remaining 1/3 - 1/4 of the time they fail with the same error as before:
Event Viewer shows an Event 5 error "The backup operation ... has failed with following error code '0x80070020' (The process cannot access the file because it is being used by another process.)." and Server Backup shows "Error in deletion of [C:\System Volume Information\001.dat] while pruning the target VHD: Error [0x80070020] The process cannot access the file because it is being used by another process."
I tried changing the backup destination from the RN316 to a domain joined Windows 10 version 1511 Pro machine and the backup worked every time.
The RN316 is domain joined. The Windows Server is 2012 (not R2).
