type “gpedit.msc” into the Run dialog box, and press Enter.

Navigate to Local Computer Policy > Computer Configuration > Administrative Templates > Windows Components > BitLocker Drive Encryption > Operating System Drives in the left pane.

Double-click the “Require additional authentication at startup” option in the right pane.

Select “Enabled” at the top of the window, and ensure the “Allow BitLocker without a compatible TPM

Close the window

There is no need to reboot. You can encrypt your drive now.