Today, Microsoft has released a new Windows 10 build for Windows Insiders, and Brad has a full write-up about what’s new. But what I’m particularly excited about is a major change to product activation: With this build, Microsoft will now let customers enter a Windows 7, 8, or 8.1 product key to activate Windows 10.

This is a major change, and one that I think will address an issue that I and many other upgraders have experienced: That is, when you clean install Windows 10 after have already upgraded (from Windows 7 or 8.1), it is supposed to auto-activate. But many times it does not, and when customers contacted Microsoft support, they were told they would have to install the old OS again, and then upgrade again. To be clear, this is not how this system is supposed to work.

Here’s how Microsoft describes the change.

“We have received a lot of feedback from Insiders on making it easier to activate Windows 10 on devices that take advantage of the free upgrade offer to genuine Windows by using existing Windows 7, Windows 8 or Windows 8.1 product keys. If you install this build of the Windows 10 Insider Preview on a PC and it doesn’t automatically activate, you can enter the product key from Windows 7, Windows 8 or Windows 8.1 used to activate the prior Windows version on the same device to activate Windows 10 by going to Settings > Update & security > Activation and selecting Change Product Key. If you do a clean install of Windows 10 by booting off the media, you can also enter the product key from prior Windows versions on qualifying devices during setup.”

If I’m reading this correctly and not missing anything, it means that you can use any Windows 7, 8, or 8.1 product key to activate an upgrade or clean install of Windows 10. I assume that certain keys—like those provided with a PC—will only work on the same PC for which the PC was created. But this still a big improvement over what was already a very generous system. (Assuming it worked properly, which it did not all the time.)

This also calls into question the point of the free Windows 10 upgrade, however. As I’ve written in the past, the year-long free Windows 10 upgrade promotion was never about giving customers free copies of Windows 10. It was about getting as many PCs already out in the world as possible upgraded to Windows 10. That is, Microsoft is trying to eliminate as many older Windows versions from circulation as possible in order to make it easier to keep the installed base up to date with new features and, more important, security updates.

I get questions about this all the time. For example, just this morning someone on Twitter asked me the following (which I’ve edited for non-Twitter clarity):

“It would be nice if, when installing Windows 10, you could enter the product key from a previous version. I’m building a new PC and have an unused Windows 8 upgrade license. So I have to install Windows 7, Windows 8, then upgrade to Windows 10 before wiping and clean-install Windows 10.”

Yeah, that would be nice. But it completely bypasses the point of the free Windows 10 upgrade, which isn’t to give you a free copy of Windows 10 for a previous Windows license you never used. It’s to upgrade existing, in-use PCs to Windows 10.

But the thing is, if this new policy is what I believe it is, this guy’s wish has come true: He can use the product key from the Windows 7 license and just clean install Windows 10. There’s no need to upgrade multiple times and then clean install.

This will require lot of testing. And I am very happy to do that. 🙂