Hello Luxandr,
Thank you for reaching out to the Microsoft Community and I'll be glad to assist you today.
I am sorry that you are experiencing the issue. Suspending BitLocker could be a potential solution. Based on the issue description, it appears there may be operating system file corruption or problems with your Boot menu, possibly triggered by another program. You can try disabling the BitLocker recovery key prompt first, which appears during each restart or startup first, and see if this resolves the issue.
a. Open Command Prompt as Administrator, type or paste the command below and click enter:
Manage-bde -protectors -delete C: -type TPM
Once completed, type or paste the next command below and click enter:
Manage-bde -protectors -add C: -tpm
• Once finished, restart your computer and see if it fixes the issue.
Similar thread (for reference):
Turn off the need to enter BitLocker Recovery Key-
https://answers.microsoft.com/thread/5e9cbc12-6...
I hope this information helps. If you have any questions, please let me know and I will be happy to help you further.
Best regards,
Gunasekar N