I have been dealing with issues where the empty space on the C drive always goes to 0. I would run through the normal steps to empty space. But, the space would always be taken back down to 0. This is problematic because I cannot install any programs or future Windows Updates.
After some searching and working, I found the culprit to be Volume Shadow Copy (see reference here). What is odd is that the System Restore was disabled in sysdm.cpl. But, when I ran vssadmin list shadows, there were 9. I went ahead and deleted them all using vssadmin delete shadows /For=C:.
But, I have no idea what could have created these Volume Shadow Copys to begin with. I ran Windows Defender Deep Scan, BitDefender AntiVirus scan, and MalwareBytes scan and they did not show any detections. I also ran the Eset NOD32 online scan, but there were no detections. From what I can tell, my PC has demonstrated no malware-like behavior and this system is used for personal finance purposes only.
Is there any additional root cause analysis that I can perform to understand what caused this issue to arise in the first place? Any help is greatly appreciated.