Hello PaulGerst,
Thanks for reaching Microsoft Community. We're sorry to learn that you were having a problem signing in to your device.
This may be due to software conflict or corrupted system files on the device. Please try Forcing a shut down and restart your Surface then see if it allows you login after the restart. But if issue persists, please give these methods a try:
- Boot to recovery menu and perform a Startup repair. On the sign in screen, hold down the Shift key and click the Restart icon. This should route you to Choose an option screen.
- From Choose an option screen, click Troubleshoot > Advanced options > Startup Repair. Wait for it to complete. Then, check if you could now login.
Feel free to respond on this thread to let us know how it goes.
Regards,
StevenK