My Passport Essential 500Gb - Backup of two users on same PC

We have two user ID’s set-up on our laptop. My Passport has successfully backed up my [Admin] user profile however it does not seem to have backed up my wife’s User Profile.

When she logs on, WDSmartware Icon appears in the system tray and when opened just shows my existing backup. It doesn’t seem to recognise my wife’s additional files.

Is this normal and am I not able to back up my wifes files or am I missing something?

Help appreciated please.