A system was running GUID partition tables (GPT) in place of MBR and UEFI instead of BIOS. After a restor from backup, when trying to enable BitLocker, I got an error saying, “Element not found”. This vague error message did not provide any helpful results on Google, so I tried running BitLocker from the command line. Running the command “manage-bde –on C: -tpmandpin” gave me an error code (0x80070490) to go with the vague message. A Google search for the error code yielded this link to TechNet that says this is a known issue when moving hard drives between systems using the UEFI boot firmware and that running “bcdboot %systemdrive%\Windows” command will fix it. The command did not fix the problem, but it pointed me in the right direction. Some more searching led me to this link that talks about how to manually delete the “bootmgfw.efi” file in the UEFI boot partition. After deleting the file and then running the “bcdboot” command from the TechNet article, BitLocker encrypted the drive.