VPS showing low disk space despite there is nothing major on it

Hello experts,

On my VPS server I was trying to see the used disk space and when I open My Computer it shows 17.9 GB free out of 39.8 GB it means that 21.9 GB space is used.

However, when I select all files and folders from C: and try to see the total size, it just count approximately 11 GB. The difference is around 10 GB. Where is this 10 GB going if I have not stored anything else here?

I asked above question from my VPS provider and he responded below

Check hidden files/system files/etc. This is default windows OS and its utilization and not specific to setup. If you want specifics of usage, you can go ahead and get in touch with Microsoft support team and they'll provide you with exact specification of the same.

I am sure that Windows OS must not be taking up 10 GB space for hidden files and folders. My VPS has Windows Server 2008 R2 installed.

Can anyone help me in this on who is right?

From serverfault SheoNarayyan

• Check and see if you have shadow copies configured. Shadow copies allow you to restore previous versions of files in a NTFS file system. Shadow copies don't show up in the normal file structure, but are taking disk space. Normally the default is that the shadow copies won't take more than 20% of the disk.

  From Knox