When we download Windows 7 ISOs, we can install Windows without a product key, for a 30-day trial. With the official Windows 8.1 ISOs, though, by default we can't skip entering the product key during the installation. Let's see how to Install Windows 8.1 without a product key.
The Magic "ei.cfg" file
We can somewhat understand Microsoft's point of view when they made the product key mandatory for a Windows 8.1 installation. It sort-of makes sense as an anti-piracy measure.
With the Windows 7 30-day trial, one could install Windows and have them for free, just by formatting and reinstalling once every new moon.
Also, one would need to have Windows installed if they wanted to run an activator, should they swing that way.
So, Microsoft decided to cut the problem off at the root. Mandatory product key equals no trial, equals no activator. Makes sense, doesn't it?
And then, they made it easy to bypass this system. And, when we say "easy", we mean "child's play" easy. Cause that's Microsoft for you.
The only thing we need is to create a notepad file, on any PC.
Then we type exactly the following:
[Edition ID] [Channel] OEM Retail [VL] 0
The only "hard" part is that when we save the file, we don't leave the default "Text documents" on "Save as type".
We select "All Files" and type the name "ei.cfg".
The result is a file ei.cfg that has a type "CFG File".
We 're halfway there. With this ei.cfg file, we can Install Windows 8.1 without a product key.
We just need to get it in the Windows 8.1 installation medium. And that's easier done than said.
How to Install Windows 8.1 without a product key from USB
The easiest way to install Windows 8.1 without a key is by creating a Windows installation USB drive.
After that, it's just a matter of dragging our ei.cfg file and dropping it in the "sources" folder in the USB.
That's it. Once ei.cfg is within the "sources" folder...
...we can install Windows 8.1 without a product key. The Windows installer won't even ask for one, it will straight up begin the installation.
The installation will ask for a product key after the first automatic reboot, but there will be a handy "Skip" button.
Of course, Windows are not activated. We will need a valid product key for that.
How to Install Windows 8.1 without a product key from DVD
Sometimes, using a Windows installation USB isn't an option. Maybe we don't have a USB flash drive, or an old motherboard might not support boot from USB.
In this case, we need to edit the ISO file so we can add ei.cfg before we burn it on a disc.
For this, we will use the 30-day trial version of gBurner. It's one of the few free apps that can edit a 2GB+ ISO, no questions asked.
We will find it at http://www.gburner.com/download.htm
We need to be really careful with the installation. If we blindingly click on "Next-Next-Next" gBurner will install useless third-party programs on our computer.
So, we need to avoid the "Ad-Aware Web Companion" installation, by selecting "Custom Installation" and unchecking all the checkboxes.
We also need to uncheck the TuneUp Utilities installer.
Alternatively, we can use Unchecky, to make sure no third-party apps are installed:
Safe Installation for All Free Apps with Unchecky
Finally, on the final screen after the installation is complete, it's a good idea to uncheck the option to associate .iso files with gBurner. Especially if we will only use it for the 30-day trial.
After gBurner starts, we select "Continue Unregistered".
We click the "open" icon and select the Windows 8.1 ISO.
Once loaded, we select the "sources" folder, click on "Add" and choose the ei.cfg file.
Once we make sure ei.cfg was added correctly in sources, we select File -> Save As...
We select a different name for the ISO, so we will have the clean ISO as a backup, in case something went wrong.
And that's it. We can right-click on the new ISO, select "Burn disk image", and we 're good to go.
You might have noticed that the new ISO is a bit smaller than the original, even though we added a file. Apparently gBurner does some slight compression during the ISO creation process.
This won't matter for the Windows Installation, though, either if we burn this ISO on a disk or use it to install a Windows virtual machine. It will work just as well.
Did you have any trouble installing Windows 8.1 without a product key?
If you had any problem with the above and couldn't install Windows 8.1 without a product key, leave us a comment.