Losing space for no reason

[FILMsomeSTUFF33]

I’ve been using Bandicam for a short while now and I’ve only recorded a few short videos to test out how Bandicam works. But I keep noticing that even after I’ve deleted all Bandicam videos and ran CCleaner, I still keep losing space. I started with 81 GB and now it’s at 77.9 GB. How do I prevent this from happening and how can I get my old space back

[Bandicam Company]

Hello,

Could you tell us how to confirm the space?
It might be the space reserved for Windows OS to run other applications and processes.
In that case, the deleted space might be occupied by the OS when you restart the OS.

Thank you.