Troubleshooting › Plan, Job, and Settings Related › Failed to Perform Backup of a Virtual Disk. System error=[The device is not ready(21)]

Failed to Perform Backup of a Virtual Disk. System error=[The device is not ready(21)]

Valid on Windows platforms.

Symptom

When a network error occurs or a Hyper-V server is rebooted while the backup is in progress, the activity log specifies that the error can be a network error or a file system error.

Solution

Restart the backup job again after the Hyper-V server restarts.