Impossible to connect to Windows Lightsail instance

Hello,

Thank you for reaching out. For what I can see the backup has been transferred to EC2 for further troubleshooting and now facing an OS issue.

Since Snapshots are not done automatically, you can go back only as far as they were taken manually, this is for either EC2 or Lightsail. Now that you are using EC2 for troubleshooting, you can try using Ec2Rescue with a helper Instance by following the documentation below (1). Here you should be able to go back to a Last Known Good Configuration by attempting to overwrite disk signature on BCD, remove Firewalls or check what else could be wrong.

As you would be detaching the root volume and attaching it to a helper Instance, here you can also check on logs, event viewer, folders and even recover some files in the event you decide to rebuild.

I hope this information is helpful. As a quick reminder and to set expectations, while system administration tasks, OS and application issues fall outside of the scope of AWS support and the Shared Responsibility Model (2-3), in AWS we are always happy to assist as every engineer provides their best knowledge to help resolve all we can even beyond our scope as best efforts.

References

(1) Use EC2Rescue for Windows Server GUI

(2) AWS Premium Support Scope

(3) AWS Shared Responsibility Model

Adding to the above, please consider troubleshooting this issue using the AWSSupport-TroubleshootRDP automation runbook.

NOTE: You can only run this on/against the instance you have migrated to EC2 and NOT on LightSail.

There is a video on how to use run the AWSSupport-TroubleshootRDP automation runbook here.