Hello,
You need to log in to the Microsoft account where the BitLocker key is stored and find the BitLocker key in order to log in to your computer.
Or you can try to find Bitlocker recovery key by referring to this link:
Find your BitLocker recovery key - Microsoft Support
If you still can't find the correct key, the only solution is to reinstall the system.
Important: Microsoft Support is unable to provide, or recreate, a lost BitLocker recovery key.
Best Regards,
Hania
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