Why I still have these two folders on C even after I upgraded, activated, format and install clean windows 10 pro on my PC. Together they are 90kb, so no big files. I also have bootsqm.dat, why is that there? I dont have those on a laptop.
After a fresh install Windows uses these folders to install a few more updates. Update a few more times. Install Ccleaner and you'll notice that it will remove it for you safely. You can manually delete it too, but ccleaner will verify these as old windows updates.
Windows has Disk Cleanup utility already included. Run it as Administrator and check all the boxes. It will clean up those residue folders and files.