One of the major “feature” of Windows 10 that will surely get many Windows enthusiasts on the cloud nine has finally been confirmed. That’s the ability to clean install Windows 10 with the free upgrade license offered to Windows 7 and Windows 8.1 users.

Since the announcement that the free Windows 10 upgrade is only available for a year, many people has been bugging by questions of what would happen if they decide to perform a factory reset to original default, do a clean install, or reinstall Windows OS after a year.

Gabriel Aul, the head of the Windows Insider program, announced it on Twitter that clean install for Windows 10 is allowed once the PC is upgraded to Windows 10 when responding to question on state of Windows 10 free upgrade license after July 29th, 2016. In other words, firstly upgrade to Windows 10 from Windows 8.1 or Windows 7, then you’re free to do whatever you want on that device with Windows 10, including clean install.

Gabriel Aul stated:

Then, he also said:

He also confirmed on separate tweet:

Finally, Gabriel Aul appeared to confirm or at least implied that the downloadable ISO of Windows 10 would be provided for clean install:

Apparently, Microsoft may be recording the hardware specification and other information on the systems that upgraded to Windows 10 from Windows 7 and Windows 8.1, as reactivation of Windows 10 on these PCs will be automatic on subsequent installs. Most likely, the reactivation of Windows 10 is verified against SLIC table in the UEFI to determine which Windows version came with the PC and authenticate a clean Windows 10 install, or Microsoft may validate and then upgrade the product key used on the system to allow future installs. Thus, it’s likely that no new Windows 10 product key is issued to upgraders, and existing Windows 7 and Windows 8.1 product keys are not working with Windows 10.

Here’s the summary on what’s allowed on reinstallation of Windows 10 based on Gabriel Aul today’s tweets:

  • Wipe the computer and clean install Windows 10 directly with ISO
  • Reset the PC (either keep or remove your files) through Settings app. This method will return the user back to clean Windows 10 on the device, as confirmed on Microsoft Community.
  • Factory reset the computer through manufacturer provided DVD or recovery method. This method will reinstall Windows 7 or Windows 8 or Windows 8.1, or whatever OS contained inside the OEM recovery image. User will need to manually install all updates and service packs, and then upgrade to Windows 10 again. It will works even after July 29th, 2016, as long as the device has upgraded to Windows 10 before, as mentioned in Microsoft Community.

Windows 10 will arrive on July 29th, 2015.

Windows 10 - Important Information