Issue
Backups for a protected endpoint complete with a warning that states, "Error 307: Volume has less than 20% disk space available: May be insufficient to complete a VSS snapshot for backup job."
Environment
NinjaOne Backup
Cause
NinjaOne Backup generates alerts when the free space on a volume drops below 20%, the minimum threshold necessary for Volume Shadow Copy Service (VSS) snapshots to complete backups.
Resolution
While this notice is just a warning, we recommend that you free adequate space on the volume to ensure the success of future backups.
Microsoft recommends maintaining a minimum of 10% free disk space per volume for general VSS usage. However, NinjaOne Backup may require up to 20% free disk space.
Additional Resources
For additional troubleshooting guidance, refer to NinjaOne Backup: Troubleshooting Error Codes.