This guide will help you turn on BitLocker for a drive without a Trusted Platform Module (TPM).
Example: Sometimes when trying to turn on BitLocker for the C: drive, you’ll get an error saying:
“A compatible Trusted Platform Module(TPM) Security Device must be present on this computer, but a TPM was not found. Please contact your system administrator to enable BitLocker.”
Resolution: Enter “gpedit.msc” in the search box of the Start menu, and press Enter.
Navigate to Local Computer Policy\Computer Configuration\Administrative Templates\Windows Components\Bit Locker Drive Encryption\Operating System Drives, then double click on Require additional authentication at startup.
Click Enable and make sure the check box next to Allow BitLocker without a compatible TPM is checked. Click on Apply, then OK and close the Local Group Policy Editor window.
You can now go back and encrypt your C: drive, using a USB memory stick as a Startup key.