Starting June 2015, Microsoft aggressively began to push Windows 10 to its existing users. The push came in the form of an app called Get Windows 10. It installed with an update and appeared in the system try. It could check your system (hardware and apps) for compatibility with Windows 10 and allowed you to reserve a copy of the new operating system. The update did something else though; it also downloaded files to install Windows 10, regardless if you reserved a copy for it or not. Users suddenly found their main Windows drive short on 6GB with nothing to account for the used space. It turned out to be KB 3035583 and one other update that were responsible for the used space; it was downloading Windows files to a folder called $WINDOWS.~BT. To recover lost space, the folder had to be deleted and the updates responsible for the files had to be hidden so that they didn’t install again. Unfortunately, the update is back and very likely to install itself again unless you hide it. Here’s how to hide the update and why it’s back.
Updates that have been hidden can appear again if a new version of the same update is released. That’s the case with KB 3035583; not only has it received an update (thus unhiding it), it’s status as an ‘Optional’ update has been changed to ‘Important’. If, after hiding this update on your system you decided to let Windows automatically install Important updates from Microsoft, it is likely the update has been installed on your system (again).
If it has been installed, uninstall and hide it again. To hide an update, go to Control Panel\System and Security\Windows Update and view the list of Optional updates. Right-click KB3035583 and select Hide from the context menu. If it has been installed, uninstall and hide it again.