After moving drive to another machine and attempting to turn on BitLocker, receive error 0x80070490 "Element not found".


BitLocker uses the Boot Configuration Data (BCD) store to detect the path to the Boot Manager (bootmgfw.efi) on a computer with Universal Exensible Firmware Interface (UEFI) boot firmware. However, if the device entry in the BCD store does not match the current set of devices, the device entry will be deleted.  This entry can also be deleted by an administrative user, although that is less common. 

Without the boot device entry, BitLocker will fail to create or update a TPM protector which happens when you initially turn on BitLocker or when protection is resumed, and the BitLocker protection operation will abort.



From an elevated command prompt, execute the following command:
bcdboot %systemdrive%\Windows