Missing free space

[CallMeDave4]

The D partition on my parents' laptop is showing only 27GB free of 229GB when viewed in Windows 7 (using either properties or disk management). However there are only 6GB of files on the D partition. So 196GB are missing. I have revealed all hidden folders / system folders / etc in the folder options. The operating system is on the C partition. C shows 3GB free of 58GB (which appears to be correct). When I use a third party program to check disk space, e.g. SpaceSniffer, it tells me that the D partition has 196GB either "free" or "unknown".
The drive has been scanned and defragged. I've run Spybot and Malwarebytes and Avast is running. Recycle bin has been emptied, temp files removed, etc. I thought the problem might have been malware hiding the disk space, particularly because my family had installed some kind of tune up software (the kind that constantly pops up and tries to sell you solutions). I uninstalled it months ago but I failed to notice the space problem until now so I don't know if there is any connection.
I'll be grateful for any suggestions.

Laptop i5
Windows 7 home premium 64 bit

(I'm not sure if this belongs in hardware but since I don't know what the source of the problem is I'll post under hard drives).

 

[WyomingKnott]

My first guess would be that the D drive is a partition that is smaller than the whole drive. Can you take a peek in Disk Management and see what size the partition is?

My second would be that the partition is formatted with a filesystem other than NTFS which has a smaller size limit; the total you mention is close to 32 GB.

My third would be to download WinDirStat and run it from an admin account. This tool does an excellent job of telling you where everything is. Just enable to option to show hidden space.

Let us know what you find, and we can suggest the next step

 

[captaincharisma]

my guess is that it is just a partition that was just made for the recovery data and they have some weird way of hiding files. check to see if there is a program starting up with windows that hides content. i remember HP did something like this back in the day. you can chack startup files by using the MSCONFIG command

 

[CallMeDave4]

Using WinDirStat I've found the discrepancy. Windows backups and system images were taking up most of the space. Going to properties for these folders / files in Windows it told me they were either 0 bytes or a few hundred MB. However WinDirStat showed they were actually 200GB combined.
Seems pretty obvious now but I assumed that since Windows displayed the backup files it would give me an accurate description of their size. Oh well, live and learn. Thanks for the input.

 

[WyomingKnott]

That stuff is usually on the C: drive, which is why I didn't post the usual litany of things to check. You can disable, or reduce the size of, go-back points. I think that go-back points are brilliant. I don't use them, but that's because I just go to my backups.