Now we cannot do anything at this stage other than a clean install, though the system could be restarted with its original settings again.

Windows 11/10 Setup has failed to validate the product key

If you are facing this issue, restart the system and try the following preliminary checks:

1] Check for Updates

Verify that the latest Windows Updates are installed on the system.

2] Run SFC scan

Run the SFC scan on the system. System File Checker helps detect and repair damaged system files.

3] Delete the temporary files

Delete the temporary files. To do so, press Win + R and open the Run window and type temp. Press Enter to open the temporary files window and delete all the files. Repeat the process with the Run commands %temp% and prefetch.

4] Try upgrading using Windows Update

If it is for the edition upgrade, we could perform it using Windows Update instead of the ISO. Though if you were considering the ISO file in the first place, you must have known your reason right.

5] Disconnect from the domain

For domain-joined systems, remove them from the domain temporarily. A good reference to help with the same could be checked on Microsoft’s website here.

6] Disable third-party anti-virus software

Remove all third-party anti-virus software of the system temporarily to isolate the possibility of their interference. If all of the above-mentioned attempts don’t work, you could try the following fix. However, doing so involves a clean install of the system so it is advisable to backup your data well in advance.

1] Extract the ISO file contents and use them

Extract the ISO file using Ashampoo ZIP free decompression software.

2] Use this Notepad file

Open a Notepad file and copy-paste the following content in it:

Save this Notepad file by the name ei.cfg to the Sources folder inside the setup ISO file.

3]  Now run the setupexe

Run the setup.exe file to start the installation wizard. You could also try making a bootable USB out of the file and run that USB for a repair or re-install. Let us know if this helps you!