Unable to create a backup in Plesk: Failed to exec backup_restore_helper: Exit code: 3: System user unavailable

Symptoms

• Backups created in Tools & Settings > Backup Manager display a warning:

PLESK_WARN: Warning: Extension "Git"
Unable to back up extension. Error: Failed to exec backup_restore_helper: Exit code: 3: System user unavailable

• Git extension version 2.3.0-383 is installed on the server

Cause

This behavior is caused by a Git extension bug, which has already been resolved in version 2.3.1-386. The warning does not affect backup integrity and is purely cosmetic.

Resolution

Update the Git extension to the version 2.3.1-386.