Drive does not show in Backup target pane

My new 4TB My Passport to which I have done one full backup of my PC. C and K drives does now not now show in Backup Target list and as such does not allow me to retrieve from this disk back to my PC. However it shows in the list of drives on my PC available for backup. I need to retrieve from the 4TB drive some files. Help?.

Hello,

What backup software did you use?

Hi… I used the WD Programme I got with a previous 2TB Passport drive. I
tried deleting the original WD apps and reloading the programmes that came
with the new 4TB disk without success.

Marty