Searching through WD Community forum lead me to the helpful post by @dankar69: Drive Erase Fails - #9 by dankar69.
I had to do a bit more. As I was backing up the same laptop and had copies of the original files on it, I could delete the full backup and start fresh. Also, my laptop was upgraded from Windows 7 to Windows 10, and wanted a clean backup image. But I didn’t want to go through a ‘Disk Erase’ and reinstall SmartWare. Here is what I had to did.
First completely deleted all contents under the folders "computer name’ (had the recovery image), WD.SmartWare.swstor and WindowsImageBackup. You need admin password for these. Once done, My Passport disk fully freed up, except for about 4GB. Smartware and WD Drive Unlocker worked fine. I was able to do a fresh backup and retrieve files smoothly.
