Hi Martin,
Thanks for your post. Before moving on, can I know if you are using Win 11's built-in backup app or 3rd party backup software?
Click Start > Run > services.msc and click OK. When services.msc opens, find Volume Shadow Copy and double-click it. Make sure its Startup type is set to Automatic. And if listed in services.msc, make sure Microsoft Software Shadow Copy Provider is also set to Automatic startup.
Then exit services.msc and reboot. Go back into services.msc and confirm that those services are running. Next, manually set a System Restore point for the boot drive. Then see if you can run the backup now.
Best Regards,
Ian Xue
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