Reposting here after getting no love at dpreview. I have 2 Windows 10 computers. One a normal desktop, one a SurfacePro4 tablet. Over the last 2 weeks both suffered significant bloat on the system drive. I've cleaned them up, but I'm curious of the cause. I'm suspicious of Photoshop 2020, because that's the only installation I've performed on both units during the time frame.
The desktop had 20 files in the C:\System Volume folder totaling 16 gigs. These looked like System Restore/Shadow copies. Strangely, they were all dated at 1:00 am on successive days. Using the System Restore dialogue to delete all restore points did not remove the files. Neither did the OS disk cleanup utility. I had to use the "VSS" command prompt utility to set the max restore file space to the minimum 1GB. They immediately disappeared.
The SurfacePro4 had over 50k files totaling 116gb in the Windows/Temp directory. The files began with "APPX" followed by a long hash string. Disk Cleanup didn't touch them, but a manual delete was OK.
I'm hoping there are some Windows gurus here that can shed light or point me in a direction to further investigate. I suspect this bloat will return.