Is my SSD Dying? 200GB missing

I have had an OCZ Revo Drive 3 x2 PCI-e 240GB SSD for a few years now. My PC randomly froze the other week (after doing some Windows 7 updates, could just be a coincidence) and after a hard reboot the PC would not boot into the OS; after a bit of diagnosing I noticed the primary partition somehow showed up as RAW. Long story short; I reformatted the OS and upgraded to Win10. This worked for a few days then it would not boot again but the partition was still NTFS. Further diagnosing looked like it was incorrectly configured UEFI BIOS (changed first boot option to Windows boot loader instead of UEFI HDD, even though it worked for a few days), fixed the problem.

I have noticed today however that the drive is almost full (15.8GB of 223GB). That cannot be right. I point everything towards a mechanical drive and have no paging file and disabled system restore. I ran WinDirStat (included screenshot) and it shows that the drive is 39.8GB, not 223GB. Is this dying or have I effed it up by trying to repair my OS (things like CHKDSK /R etc.)?

Can any one shed any light on my problem?

Kind regards

-Adam

In the WinDirStat menu,

In Options select on Show Unknown and see if that makes a difference in what is displayed.
You could also select Show Free Space and see what that does.

Hi DavidE

Yeah, that's different.

This should be a bit more helpful.

Try WizTree (free), it often shows files WinDirStat can't.
They have a portable zip available, no install.

Antibody Software - WizTree finds the files and folders using the most disk space on your hard drive

WizTree does not look like it shows much.

WinDirStat however is showing 167.3GB of unknown. What's that all about? Is there a way get that back?

This build is less than 1 week old...
Plus all my data is on the mechanical drive anyway, but still...

And if that is in fact the only recourse, what have I done in that short time to cause this. I have literally just installed Drivers, updates, Steam, GOG Galaxy and played Witcher 3 a little.

If WinDirStat and WizTree can't show files correctly,
from what i've read you might need to boot the PC with a Linux bootable CD/USB to try and find where all the "unknown" space is used.
You also have Win 10, so that might make a difference.

I've never had to use Linux for such a problem, so i can't help with that.
You can wait for others that have experience with that to post here.