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Jump To: Support > KB > Windows > Windows10Upgrade

How to do a clean installation of Windows 10 instead of an upgrade and still be licenced


Since Windows 10 was launched, Microsoft have offered a free upgrade for computers running Windows 7, 8 or 8.1. This offer expires on 29th July 2016 and after that, the cost for Windows 10 Home will 99.99.

The upgrade process assumes you will run do an in-place upgrade (if you are fed up of being nagged about it, remove KB3035583!). As part of this, it ensures that your existing copy is licenced and that the new version will also be licenced. As part of this upgrade, your computer is registered with Microsoft (so you require Internet access), so if you subsequently do a clean install it will be automatically activated.

You may not want to do an in-place upgrade for a number of reasons:

  • You don't have the disc space for the upgrade files, the new version of Windows and the old version of Windows to be present at the same time.
  • You want to upgrade at a convenient time when you believe that Windows 10 is good enough for your needs
  • You may want to install on a different disc
  • Windows may refuse to upgrade on your hardware even though a clean install works (e.g. it claims a graphics card is not supported)

If you do a clean install, then you will be asked to enter a product key. If you previously did an in-place upgrade, you can click Skip and the computer will be automatically activated. If installing from a recent build of Windows 10 (build 10565 or later), you will be able to use your existing Windows 7, 8 or 8.1 product key to activate. However, it is not clear how this works with the upgrade offer; will existing codes be rejected after 29th July?

One way to play it safe is to manually run the registration process on your existing activated installation of Windows. This will generate a file called GenuineTicket.xml which you can store somewhere safe and copy back on to activate your new installation. This will work with all versions of Windows 10, not just recent builds.


  1. Check you have a working Internet connection
  2. Locate a Windows 10 ISO or DVD
  3. Open the ISO image or DVD and go into the sources folder.
  4. Copy the file called gatherosstate.exe to your hard disc (e.g. onto your desktop).
  5. Right-click on the copy of gatherosstate.exe and choose Run as administrator. N.B. do not try to run the copy from the ISO or DVD
  6. If you see a User Account Control window, click Yes to confirm you want to proceed
  7. After a while, a file called GenuineTicket.xml will be created alongside the gatherosstate.exe program
  8. Copy GenuineTicket.xml to a safe place off your computer (e.g. a USB stick) as when you re-install the disc will be wiped
  9. Do a clean install of Windows 10
  10. When prompted for a product code, click Skip
  11. After installation, open File Explorer and go to:
  12. Copy your GenuineTicket.xml into the GenuineTicket folder. You will probably be asked to confirm that you wish to copy
  13. Restart the computer
  14. Check the activation status by going to the System control panel and looking at the bottom of the window (you may also run slmgr /xpr from a command prompt to check it).
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Page last modified on May 06, 2016, at 09:36 AM by sborrill