When you update your system from windows 7 or 8 to windows 10, a copy of the old system named ” Windows.old ” will be saved for some rare times you need to go back to the the old system. If you are sure that you don’t need it you can delete the folder to save memory space. But deleting it is not just choosing ” delete ” from right click menu!
Search the phrase ” Free up disk space by deleting unnecessary files ” and click on it. Then choose your intended drive and OK it. After scanning is finished, click on ” Clean up system files ” and then OK it. Then tic the check box ” Previous Windows installations ” and OK it.