I am having trouble downgrading from Windows 10 to Windows 8.

I have retrieved my Windows 8 product key and created a Windows 8 installation image using a tool that I downloaded from the Microsoft website. I now have a Windows.iso file on my desktop.

When I run setup.exe I choose whether or not I want to install updates and enter my product key which is accepted but when I try to go to the next step this error message appears:

Something happened: Setup has failed to determine supported install choices

What is the best way to proceed here as I am at a loss what to do and I need to get this computer downgraded back to Windows 8 as soon as possible?


6 Answers 6


Are you in the position to reformat it? Burn the .iso to a CD, pop it into your computer and restart. When you're in the BIOS screen you should see an option such as 'press F12 for boot options'. Hit the key it tells you to press and boot from the CD-ROM.

Then run through the settings to reinstall Windows 8.

  • 2
    To add, downgrading any version of Windows from within Windows is not a supported scenario, so a clean install from bootable media is the only "official" way of doing it. Though it doesn't usually need a reformat, Windows will (if there's space) move the old Windows install into a Windows.old folder if you choose to reinstall to the same disk without reformatting.
    – qasdfdsaq
    Commented Jun 10, 2015 at 10:33

If your scenario is that you have installed Windows 10 over Windows 8, and you have kept the resulting folder C:\Windows.old, then you can use it to return to Windows 8. This was always possible in the Windows 10 Technical Preview.

This is the procedure :

  • In the Windows 10 Start menu select Settings
  • Click Update & Security
  • Under "Go back to a previous version of Windows", click Get started
  • Enter something into the "Why are you going back?" screen
  • Click Next and wait, as this will take some time
  • You will need to have your password to Windows 8 once the process is finished.

On one version of the Windows 10 Technical Preview, the "Why are you going back?" screen is replaced by a "What you need to know before you go back" screen, where you click on "Go Back" instead of "Next".

You may find that the shortcut to Windows Explorer in the taskbar has stopped working. To fix, right-click the icon, unpin it from the taskbar, then search for Windows Explorer in the Start menu and drag it to the taskbar.

This is explained in detail with screenshots in the article : How to downgrade Windows 10.

If you have deleted the Windows.old folder, a clean install of Windows 8 is in my opinion probably the only remaining option.


Based on some leaked release notes on the leaked build 10147 it appears this is now possible. This means that with a future Insider Preview buil it should be possible to downgrade back to the earlier operating system.

When the user upgrades from Windows 7, Windows 8, or Windows 8.1 to Windows 10, they are now able to downgrade to the earlier operating system as expected. Before this fix, thepresence of an Internet Information Services (IIS) account prevented the downgrade.

enter image description here

This means its not currently possible ( unless you are running the leaked build ) but in a future build and once Windows 10 is released on July 29th 2015 it will be possible to downgrade to the earlier operating system.


Now that it is indeed possible you have to go through the following steps.

  1. Select Settings from the start menu. enter image description here
  2. Click Update & Security. enter image description here
  3. Select Go back to a previous version of Windows
  4. Provide Feedback enter image description here
  5. Confirm you do indeed want to perform a downgrade. enter image description here


  • Included the screenshots from the PC Advisor article. I realized after Harry's answer that I forgot to explain, how to do it, thats what I get for reading something at work without my normal resources.
    – Ramhound
    Commented Jun 20, 2015 at 18:17

You can downgrade. Just don't start the setup.exe that is in the first main folder! This one gives you this error. Go into the sources folder from this iso and there click this setup.exe inside the sources folder! Then Setup starts and you can downgrade to 8.1 within 10! No install media needed! Just mount the iso inside 10 with rightclick and attach (or how it is named) and then go into the sources folder. There click on setup.exe and it installs. I tried it on my Switch10 and it worked :)


At least it worked for me.


If the laptop in question is a Windows 8 laptop, in other words, was shipped with Windows 8, running setup from the same version, either Professional or Single Language, the installation will self activate.

Be sure to backup your stuff before hand. And just do a clean install.

Running setup from the desktop might create some barriers for a fresh install. Like the Windows.old folder or error messages such as those you are now receiving.

Also note, if the laptop is not booting from your disc, you might need to reconfigure the BOOT method from UEFI to Normal(Legacy)

If you are lucky and only did an upgrade, you can try and recover the machine to its factory defaults from the Recovery partition. You will have to make that partition active though to boot from it. Most manufacturers do have a Key Combination to launch this recovery environment. This option is most advisable if possible as it will restore drivers too.

  • 2
    This does not really explain HOW the author acomplished this.
    – Ramhound
    Commented Jun 24, 2015 at 11:52

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