Disk Cleanup App Windows 10 (Compress your OS Drive) 20.8GB - can I clean up, delete? or is it important?

Jan 8, 2019
So, I was wondering where 20Gigs of my SSD space gone to, and I found out when I checked on the disk cleanup app on windows 10 that 20.8GB of my space has been taken up by a file called 'Compress your OS drive'.

You can find that,

Search Bar > Disk Cleanup > Open and select Drive C > Scroll a bit down and you will see a large file.

So, my question is can I delete it, or check on the clean up box and press ok?
I see what is being discussed on my Win10 Pro install (although mine is a HyperV converted VM, as applies when HyperV is seemingly 'added' to a Win10 Pro), in fact it was 75 GB in size....and listed right where the OP mentioned, right click C drive, 'properties' /disk cleanup, 4th or 5th option down as 'Compress your OS drive'

But, I think this is misleading by showing it in 'disk cleanup', implying it is something that can be deleted like trash, cookies, etc...