Hi Catalin,
I'm Sumit, here to answer your query at the Microsoft Community.
Apologies for any inconvenience you are experiencing. We are happy to help you.
Let us look into this problem.
Via the article:
Troubleshoot Windows 11 upgrade and Installation errors - Microsoft Community
https://answers.microsoft.com/en-us/windows/for...
Let us check the following Logs to investigate why the upgrade to Windows 11 failed. Use a File sharing Website like Onedrive to share the files and post the link in the next response.
C:$Windows.~BT\Sources\Panther: File named Setupact.log records actions in the downlevel and SafeOS phase. As the log can be very large, the setup also creates a file named "Setuperr.log" that only has information about the errors encountered by the Setup to narrow the source of the problem.
C:$Windows.~BT\Sources\Rollback: File named Setupact.log records what happened after the update failed and Windows rolled back to Windows 10. The starting portion of the file may explain what happened and why the update failed.
Supplementary logs if present:
- Device Install Log in C:/$Windows.~bt\Sources\Rollback\setupapi\setupapi.dev.log
- Setupmem.dmp present in C:$Windows.~BT\Sources\Rollback if the PC BSODed during the process.
These folders may be hidden, so you need to either show the hidden files or paste the path in the Run Dialog box.
How to share diagnostic files/logs on the Microsoft community
https://answers.microsoft.com/en-us/feedback/fo...
I look forward to hearing from you, and ready to work with you until we reach a solution.