Check your Microsoft account at https://account.microsoft.com/devices/recoverykey
Look for a printed copy saved when BitLocker was enabled
Check a USB flash drive that may contain the recovery key
Search files or documents where you may have saved the key
Ask your work or school IT administrator if the device is managed
Check Azure Active Directory or Entra ID if the device is organization-managed
Check Active Directory if your organization stores recovery keys there
Look in your device documentation or setup records
Check any password manager or secure note app you use
Contact the person or organization that set up the device