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Fixing Backup Error 308: Unable to Determine Free Space

Issue

Backups for a protected endpoint complete with a warning that states, "Error 308: Unable to determine free space."

Environment

NinjaOne Backup

Cause

NinjaOne Backup checks the protected volume's available free space to prevent Microsoft Windows from deleting the snapshot. If the check cannot be performed before the backup begins, you will see a warning message.

Resolution

Review the endpoint's antivirus and Data Loss Protection (DLP) software to ensure they are not limiting access to see disk information.

Additional Resources

For additional troubleshooting guidance, refer to NinjaOne Backup: Troubleshooting Error Codes.

FAQ

Next Steps