Hello,
Thank you for posting in Microsoft Community forum.
Based on the description, I understand your question is related to Bitlocker.
Restart the computer, press and hold the F8 key as your computer restarts. The machine will show advanced boot options
Select command prompt and then run below command to unlock and turn off bitlocker, then retry the normal boot:
You can try use below command to disable bitlocker of that drive:
Replace <recovery password> with your 48-digit recovery key, replace C with your current problem drive letter:
manage-bde -unlock C: -recoverypassword <recovery password>
After unlock, disable bitlocker use this command, replace C with your current drive letter:
manage-bde -off C:
Have a nice day.
Best Regards,
Molly