'0x8078006B'. Windows Backup Error

That code means the backup target volume is not valid for system image storage or there is a conflict with existing shadow copies. You need to ensure the destination drive is not the system or boot volume and has sufficient free space, ideally 1.5 times the size of the source data. If the “WindowsImageBackup” folder already exists on the target, remove or rename it before retrying. Check Event Viewer under Microsoft-Windows-Backup for related VSS errors, and run vssadmin list writers to confirm all writers are stable. If snapshots are corrupted, clear them with vssadmin delete shadows /all and retry, but note this removes all restore points. Running wbadmin start backup from PowerShell can help confirm if the issue is with the backup engine or the GUI. Finally, make sure the server is fully patched with the latest cumulative updates, as some backup issues are resolved by Microsoft hotfixes.

The error code 0x8078006B during a Windows Server backup typically indicates that there is an issue with the Volume Shadow Copy Service (VSS) or the backup process itself. Here are some steps you can take to troubleshoot and potentially resolve this issue:

1. Check Disk Space: Ensure that there is enough free space on the drive where the backup is being stored.
2. VSS Writers: Run the command vssadmin list writers in an elevated command prompt to check the status of VSS writers. If any writers are not stable, you may need to restart the services associated with them.
3. Event Viewer: Check the Event Viewer for any related error messages that can provide more context about the failure.
4. Permissions: Make sure that the account running the backup has the necessary permissions to access the files and directories involved in the backup process.
5. Repair VSS: If the VSS service is malfunctioning, you might need to repair it. This can involve unregistering and re-registering the VSS components.
6. Antivirus Software: Sometimes, antivirus software can interfere with the backup process. Consider temporarily disabling it to see if that resolves the issue.

If these steps do not resolve the error, further investigation into specific logs and configurations may be necessary.

References:

• System state backup by using Windows Server Backup fails with error: System writer is not found in the backup
• Windows Server backup may fail because of the SQL Server VSS writer