I made a initial scan, it said 22% of the HDD was fragmented (180GB/930GB)
I then let it defragment the 9000 files (7.6k were files from State of Decay 2)
But now all the files that were defragmented are corrupted (verified this with other files that I knew were editable, like a revit project that I worked on the day before defraging)
Luckly I have backup from the work, and the game I can just re-download
But this is a serious issue