by John Lister on September, 16 2015 at 08:09AM EDT Microsoft has confirmed it has downloaded Windows 10 to some Windows 7 and 8.1 computers without express permission. The download comes through the Windows Update process and takes up space, but doesn't install the new system unless the user chooses to do so manually. The issue came to light when some users noticed that their hard drives had less free space than expected, then dug down into hidden files and folders to discover data related to Windows 10. In theory the Windows 10 installation file should only be 3GB, but some users have reported a 6GB file. The situation has been the source of much confusion. Originally it appeared the file had only been put on computers of those who opted to reserve an upgrade of Windows 10. Now it's been confirmed Windows 10 has also been put on PCs where the user has Windows Update automatic updates enabled. Download Provides "Smoother Upgrade Experience" In what appears to be a standard statement to the media, Microsoft said "For those who have chosen to reserve their upgrade of Windows 10 and those that have Windows Update automatic updates enabled, we may help customers prepare their devices for Windows 10 by downloading the files necessary for future installation ... This results in a smoother upgrade experience and ensures the customer's device has the latest software." (Source: computerworld.com) In principle such a policy isn't unusual with software: both updates to Windows and to several browsers work this way, with the idea being to download the update in the background, but let the user install it at a convenient time, such as when restarting a PC. The problem is that this is virtually unheard of in the case of an entire new operating system that involves such a huge file, particularly with many people still on slow connections or with monthly data use limits from their Internet provider. While it makes sense to update an existing application or system in this way, it feels somewhat presumptuous when it comes to changing from Windows 7 or Windows 8.1 to Windows 10. Windows Disk Cleanup Removes Install File There are a couple of ways to respond if you are certain you don't want to get Windows 10 any time soon. One way is to disable the option for "Install updates automatically" through the Windows Update (Windows 7) or Change PC Settings (Windows 8.1) settings menus, and instead set it to "Download updates but let me choose whether to install them". The big downside is that you will then need to manually approve any updates, which could delay getting the latest bug and security fixes. Another option is to run the Windows Disk Cleanup tool which removes any unnecessary files including the Windows 10 installation file, thus freeing up the disk space; Infopackets already has a guide which explains this process. You can then forcefully remove certain Windows Updates to prevent Windows 10 from ever attempting downloading onto your system again.