Windows 10: Problem with over 200 GB of system files

I have a 64-bit Windows 10 PC, I built it a few years ago with Windows 7 and did the free Windows 10 upgrade last year. My hard drive is a modest 500 GB but I recently I noticed I am almost out of room so I went to investigate why. When I used Windows 10 Data Usage tool, I saw that my personal files accounted for less than half the hard drive space used. System files took the other half, specifically 217 GB of System files. I looked it up and I think Windows 10 64-bit takes up 20 GB of space. What the heck is going on here then? I have a very few games- Hearthstone, Portal, etc- and some basic utility files like LibreOffice, Gimp, iTunes, etc. Any suggestions for finding my mystery hard drive hog are welcome.

:)

 

Getting Windows Ready, Don't Turn Off Your Computer

I believe I have finally resolved this problem. There was a file that accumulated uninstalled updates called CBSpersist.log that grew each time windows install failed. At the end it was over 200 GB and the windows segment of my 500 GB hd was over 200
GB leaving no room. I installed a second HD and the Tech found the file, removed it, and I am back to a system file less than 1 GB.

 

Deleted 200 GB of Data

When you got to this Window, did you click on your external drive and then click scan?

 

Since you upgraded from W7, you probably have at least one Windows.old folder that contains most of your system and programs files from previous system. That can effectively double the size on disk.
Disk Cleanup - Open and Use in Windows 10 - Windows 10 Forums

 

As well as @CountMike said you should download and run as administrator Treesize Free

That will tell you if you have some odd huge files.

My Windows 10 with Office (and MS Project which is pretty big for some reason) is less than 11GB so I think you might have some extra stuff you don't want.

What is annoying (I think so anyway) is that even if you compact your OS it is expanded when you upgrade. So for me (Windows is ~6GB) when I upgrade it will be ~17GB. It will therefore not fit. I know lots of people have more than 32GB assigned but for me it is a PITA.

 

Thanks, I found some old system files I could clean out- WIndows Restore Points had used a lot of space. I also found a program folder that had a lot of unneeded data on it using Treesize. Now I have half my hard drive space back- perfect!