Error while backing up a subscription in Plesk: Unable to back up files owned by system user

Symptoms

• Backup in Plesk fails with the following error:

  Unable to back up files from C:Inetpubvhostsexample.com owned by system user. Error: Failed to create archive: Repository error: Archiver error: unable to pack C:/Inetpub/vhostsexample.com. Archive creation failed.

Cause

Files of subscription example.com are locked by a stuck processes and Plesk Backup Manager is unable to access them.

Resolution

1. Connect to the server via RDP
2. Open Windows Task Manager
3. Stop the process RunCU.exe