The files required to install Windows 10 are being automatically downloaded to Windows 7 and 8.1 users by Windows Update even if you want to upgrade or not.

The Register reported that the upgrade files are being downloaded even by users who have not opted to digitally "reserve" a copy of Windows 10 in Microsoft's app.

It seems to be a useful move to make updates easier for people who are willing to download the new OS, but it could also create trouble because unlike regular Windows Update files, the Windows 10 update is obviously rather large. If a user has lack of space and can only download a limited amount of data, then the update could create real trouble.

Microsoft confirmed saying that "For those who have chosen to receive automatic updates through Windows Update, we help customers prepare their devices for Windows 10 by downloading the files necessary for future installation."

If you do not want Windows 10 then you must know that the bulky file can be removed in Microsoft's Disk Cleanup Utility.