A little over a week ago, some Windows 10 users may have noticed a pop-up box notifying them that an upgrade to their version of Windows was available. This is part of system update KB3159635, also known as the Windows Upgrade Assistant. This pop-up is legitimate and is designed to inform you that you have yet to upgrade to the Fall 2015 Update.
If you want to install the upgrade, simply click the next button to move through a few pages. The upgrade will begin downloading and will ask you to restart in order to allow it to install. While this upgrade is generally considered safe (Microsoft claims that “all your files will be exactly where you left them”). It is always best practice to make sure that you back up your system before proceeding.
If you don’t want to upgrade right now, simply click the “cancel upgrade” link in the lower left corner of the window. A Windows 10 Upgrade Assistant icon will be placed on your desktop, should you want to resume upgrading later.
The Fall 2015 Update contains numerous improvements to Windows 10 so if you haven’t upgraded yet, it’s definitely worth a look.