File explorer/r click os drive/properties/scan drive
cmd as administrator sfc /scannow
if errors then run
Dism /Online /Cleanup-Image /CheckHealth
Dism /Online /Cleanup-Image /ScanHealth
Dism /Online /Cleanup-Image /RestoreHealth
C:\>Dism.exe /online /Cleanup-Image /StartComponentCleanup
clean drive– run ‘disk cleanup’ as administrator and remove old windows
Run chkdsk /f
if hdd and not ssd then run mydefrag