Why there are ~50G addtional files in my backup passport Ultra

I’ve backed up (file backup) once, today I deleted back up file all in my passport Ultra, but I found there alomost 50G space has been occupied but I can’s see them from every folder.

And I did file back up again, after backed up, beside my backup file, this 50G addtional files are still remain, what are the files? how can I delete it? or should I format my passport and back up from very beginning? if I have to format my passport, how can I keep the WD files in the disk?

Thanks.

Welcome to the Community.

What is stored within your WD Passport Ultra _ outside _ the backup folder? Everything copied into your unit by means other than WD SmartWare will be listed as “additional files”.