what is your Windows version?
but you will need to go into Control Panel and either check out File History or Backup and Restore (depending on what you used) and check the settings.
make sure all your personal folder are ticked to be included.
and if you like, check the box to take a system image as well.
personally, although completely adequate, I don't used the MS inbuilt backup simply because checking the way it stores things is not straight forward as I would like. my traits I want in a backup program is;
- ability to store with no compression
- store it without changing the files/folders at all
- the software that created the backup is not needed to restore the backup
- can detect changed files and only backup those
- shows a list of what will happen so I can give it a once-over
so for my personal files, I use ViceVersa (a paid-for software) which I've used for about 15 years now.
my system images are done via Macrium.
normally you only need to recover files from your personal backup sets when files go missing or to use the backups as a versioning control method to go back 'in time'.
the system images come into their own when MS goes tits-up. very useful although I've only need them maybe 3 times ever, but they have saved my bacon and get the system back up within 1 hour.
sorry to prattle on, but backups are sort of my OCD thing.
I'm still very suspicious you got 500GB crammed into 8GB.
I'll let others chime in with their backup software choices.
I've dabbled trying to find a free replacement for ViceVersa but never found one that ticks all my boxes.
When my current version stops working on Win10 I'll move completely over to Macrium. (they wanted a re-subscription when going from version 2.0 to 2.5 which I did but now want another payment if you want v3.0, so their business model is minor versions are free but major you pay for - not for me)