My Passport fills up with repeats of old files?

My Passport has filled up using the WD Backup application. According to the manual only files that change will be backed up. Yet when I look at what I can restore, some unchanged files seem to appear listed in a recent backup (last altered in 2012). Presumably I will have to delete the files somehow or do a general erase and start again, but how can I prevent the device from filling up again? I only have a maximum of 485GB of used space on my C: Drive to backup, but my My Passport has 1.5 TB of used space and doesn’t have room for a new backup!

Hope someone can help, please?

Hello Zero_Pop_Gro,

I would suggest you to contact WD support for better assistance.

The issue seems to have fixed itself somehow. Now Windows Explorer shows that only 514GB are now used. So I don’t get messages about the device being full and I get messages showing normal completion of backups. Hopefully won’t happen again.
Thanks, Zero_Pop_Gro.