Millions of Windows 7 and Windows 8.1 users around the world are getting desktop notification from Microsoft to reserve their free Windows 10 upgrade copies. As you likely know, Microsoft is offering free upgrade to existing Windows 7 and Windows 8.1 users who upgrade in the first year of the official release of Windows 10, which will happen on 29th, July. To help users reserve their free upgrade, Microsoft has pushed out KB3035583 update through Windows Update service, and users who have installed this optional update are seeing the Reserve your free Windows 10 upgrade notification. This also means that users who haven’t installed this optional update aren’t getting the free upgrade notification despite being eligible for the free upgrade. What’s happens when you reserve your free upgrade? First things first. You don’t necessarily need to reserve to get the free upgrade from Windows 7 or Windows 8.1 to Windows 10 upgrade offer from Microsoft. When you reserve your free upgrade using Get Windows 10 app, around the 29th of July, you’ll get a notification once Windows 10 is downloaded on to your computer. In other words, this app does nothing but automatically downloads Windows 10 installation files and alerts you when Windows 10 is ready to upgrade. And the best part is, you can upgrade to Windows 10 without losing installed programs. In simple words, you can get the free upgrade without reserving, but reserving your free upgrade using this method is the easiest way to upgrade your Windows 7 or 8.1 installation to Windows 10. To reserve your free Windows 10 upgrade, please complete the following directions: Step 1: If you’re seeing the small Windows logo button in the system tray area of the taskbar (adjacent to date and time), click on it to launch the Get Windows 10 app. Step 2: Once Get Windows 10 app is launched, click Reserve your free upgrade button, enter your email ID, and then click Send Confirmation button to receive a confirmation email from Microsoft. For those who are curious, you can always cancel your reservation by right-clicking on the Windows icon (Get Windows 10 app icon) in the system tray, clicking Check your upgrade status, and then clicking Cancel reservation option. And if you can’t see the Windows logo button in the system tray (shown in the picture), it’s likely because you haven’t installed the optional KB3035583 update. We advise you to open Windows Update, click Check for updates, and then select KB3035583 from optional updates. You don’t need to restart or log out after installing the update. Finally, note that the update will appear only on computers running legitimate Windows 7 Service Pack (SP1) and Windows 8.1 with the latest updates. So make sure that all Windows updates are installed on your PC before trying anything else. Also note that if you’re running a pirated version of Windows 7 or Windows 8.1 and want to upgrade to Windows 10, please read our upgrading to Windows 10 from Windows 7/8.1 pirated guide.