Error
[MS Windows System Backup]
There is not enough disk space to create the volume shadow copy at the storage location. Ensure that all volumes included in the backup have the minimum required disk space available for shadow copy creation. This applies to both the backup destination and the volumes being backed up.
Cause
This error commonly occurs when there is insufficient local storage for the VSS snapshot to run.
Notes
- Typical VSS guidelines: Allocate at least 10% of the volume size or enough space to store several restore points.
- Best Practice: Allocate 15–20% of the volume size if you need to retain multiple restore points or perform frequent backups.
Important: VSS snapshots for bare-metal backups are significantly larger and often require more disk space than is available. The above settings may not be sufficient in these cases.
Note: Bare-metal backups must use VSS. This feature cannot be disabled to reduce disk space usage. Even if you disable VSS within BOBcloud, Windows will still rely on its own VSS implementation.
Fix: Configure Your VSS Environment
Add VSS Storage (if not enabled):
vssadmin add shadowstorage /For=C: /On=C: /MaxSize=100GB
(Replace 100GB with a value appropriate for your environment.)
Resize VSS Storage (if already enabled):
vssadmin resize shadowstorage /For=C: /On=C: /MaxSize=xxxGB
Verify VSS Settings:
Run this command in an elevated PowerShell window:
vssadmin list shadowstorage
Check VSS Services and Writers:
Ensure the Volume Shadow Copy service is running.
Then verify VSS writers are active:
vssadmin list writers
A bare-metal backup typically uses around 7 writers, all of which should report as ‘Stable’.
Advanced Troubleshooting
If the backup continues to fail, the issue may be related to hidden system or EFI partitions.
Test with Windows Backup (excluding BOBcloud):
Standard Backup Test:
wbadmin start backup -backupTarget:D: -include:C: -allCritical -quiet
(Replace D: with your actual backup destination.)
Exclude Critical Hidden and EFI Partitions:
wbadmin start backup -backupTarget:D: -include:C:
If this backup succeeds, you may need to resize the EFI partition or redirect the VSS snapshot to another drive.
