My Book worked OK as a Macbook Time Machine drive under High Sierra OS (although I had to connect the USB cable after restarting the computer to get it to work), but when I updated to Big Sur I can’t unlock it. I get the message: “You must unlock the WD Drive Unlock application from the WD Drive Unlock CD associated with the drive you want to unlock.” Well, that virtual CD drive is contained on the My Book drive itself, which is inaccessible unless unlocked! So, all my backups are presently inaccessible. Help!
OK, I think I found a workaround that works for me. (1) Go to WD Drive Utilities (if you don’t have it, you can download it from WD). (2) A blank window should come up “Attach a supported WD drive”. Connect your USB cable to your Mac. (3) When “Unlock Drive” appears in the Drive Utilities window, enter your Apple password and click on “Unlock Drive”. (4) “My Book For Mac” should now appear on Finder and you can use Time Machine. Trying to unlock my MacBook from the Finder window no longer works for me, but this does. You can still eject the drive from Finder.
