My system drive (C:) and external USB drive (D:) are both encrypted with Bitlocker.
I can unlock the D: drive with the password. However I cannot get it to auto-unlock. Checking the box doesn't do anything. At next login it still requires the password to unlock again.
If I go to "Manage Bitlocker" for the drive and click on "Turn on auto-unlock", I get the following error...
The error doesn't seem to make any sense, as the drive is already encrypted.
I don't know what it means about the system boot information, as this is a data drive which has never been used to boot an OS.
I have previously been able to get this drive to auto-unlock, but have since re-installed Windows 10, to get the SSD hardware encryption working.
Just a bit more information about the system, if it's helps.
The system drive is a Samsung 850 Pro SSD, with "Encrypted Drive" enabled through Samsung Magician.
The external USB drive is a 3TB Seagate.
The system doesn't have a TPM, so I'm using a boot password to unlock the system drive.
I have considered turning Bitlocker off and on again for the external drive, but I would really rather avoid that if possible, as it will take an extremely long time, and may not do anything anyway.