Space on Hard disks

[motim]

Hello,
On my computer are 3 hard disks, letters "C" (system), "F" and "G" both to store data. (D and E are DVD).
"G" capacity = 149 GB, used space = 23.2 GB, actually all folders and files = 20.7 GB, missing 3 GB ?
The same on the others
"F" capacity = 74.5 GB, used space = 13.6 GB, actually all folders and files = 5.54 GB, missing 8 GB ?
"G" capacity = 111 GB, used space = 51.7 GB. actually all folders and files = 30.1 GB. missing 21 GB ?
Each disk is one whole partition.
How can I find out what is on the "missing" spaces ?
To demonstrate this "riddle" enclosed here screenshots of the 3 disks and one of "disk management" window.
Hope the images won't overlap.
Answers will be appreciated.
Thanks
Motim

 

[LMiller7]

There are utilities that can do this and others can advise.

The reality is that determining disk space consumed by individual folders is highly problematic and the results only an approximation. This will be the case for any modern file system, particularly for one so complex as NTFS. Likely the biggest disk space not accounted for will be in the "System Volume Information" folder, by default present on each local drive. This will typically be reported as zero but that isn't even close. This folder contains System Restore Points and previous versions of files. This typically consumes many GB of disk space. For a variety of reasons even an elevated admin account has no access to this folder. As Windows Explorer runs under the users account it cannot access this folder and is unable to determine it's size.

Also by default hidden files are not counted in any folder.

There are third party utilities that use a service running at a higher privilege level and is able to more accurately determine disk space consumed. Windows Explorer does not do this as most IT managers would consider it an unacceptable security risk.

 

[whs]

You will never get the right number by adding up your folders. How for example are you going to account for restore points. Just use a program to enlighten you - e.g. this one:

https://windirstat.info/

And to get the size of the restore points, use this command in an elevated command prompt:

vssadmin list shadowstorage