We have received a lot of feedback from Insiders that it should be easier to activate Windows 10 on devices when taking advantage of the free upgrade offer from genuine versions of Windows 7, Windows 8 or Windows 8.1. With build 10565+ of the Windows 10 Insider Preview on PCs, if your device doesn’t automatically activate after installation, you can now enter the product key that was used to activate the prior version of Windows on the same device, by going to Settings > Update & Security > Activation, and selecting ‘Change Product Key’. If you prefer a clean install of Windows 10 by booting from media, you can now also enter the product key from prior Windows versions on qualifying devices during setup.
The product key from the prior version of Windows must correspond to the equivalent edition of Windows 10 you’re trying to activate as determined by the like to like Edition matrix for Windows 10. For example, you cannot activate Windows 10 Pro on a device that ran Windows 7 Home edition by using the Windows 7 Home product key.
If you have an OEM Windows 8 or Windows 8.1 device wherein the product key is provisioned into the device firmware by the OEM during manufacturing, Windows 10 Insider Preview Build 10565+ will automatically use the firmware product key upon rebooting after installation as long as the Windows 10 Edition matches the edition of Windows 8 that your device originally ran.
Please note that with Windows 10, we introduced a new activation technology that uses “digital entitlements” (more information available at Activation in Windows 10) that doesn’t require product keys, basically you no longer need to remember and enter product keys. Using product keys from prior Windows version to activate Windows 10 will activate your device using a digital entitlement.
Finally, once you activate Windows 10 or Windows 10 Insider Preview (Build 10240 and higher) – you’ll be able to install public releases and Windows 10 Insider Preview builds of the same edition of Windows 10 seamlessly without the need to re-enter product keys.
We’re looking forward to you trying out these changes and providing feedback.