Installing Windows 8.1 (Or 8) Without a Product Key

Windows 8.1 - Skip product key entryOne great feature Windows 7 was possibility to install them without needing a key. Instead of entering 25-digit key, you could just select skip and Windows would give you 30 days after install to setup everything before requiring valid product key.

I found this really useful during setup of a new machine when I would have multiple reinstalls while trying out various drivers and performing their troubleshooting. Only once I was perfectly satisfied with machine, I would activate it.

More than once I also used this feature to reproduce a bug in different OS language (e.g. German). Mind you, I did have keys for that particular version (MSDN subscription is a great thing) but I was regularly too lazy to look key up for a version that would essentially get installed and deleted within a day.

Thus I was really pissed off when I found that feature was missing in Windows 8. But I was wrong. Feature is still present in setup. Only now it requires some preparation first.

Very first step is to copy all files from Windows DVD. Assuming that you have your DVD at letter W: and that you want staging directory at C:\Windows81, this would be:

> ROBOCOPY W:\ C:\Windows81 /MIR

Once copy operation has completed, we need to create ei.cfg in C:\Windows81\sources directory. In my case I wanted to specify Professional edition expecting retail key so I created file with following content:


Only thing missing is creating new ISO file that we can burn on DVD. While this is not strictly necessary if you are creating bootable USB, I find having pre-prepared image an useful step. If nothing else, it is easier to backup a single ISO file than over a writable USB.

For bootable image creation we need Windows Assessment and Deployment Kit (or Windows ADK) for desired Windows version. Since I wanted to adjust Windows 8.1, I downloaded Windows ADK for Windows 8.1 but Windows 8 ADK is also freely available. Only thing that you really need to install for this guide are Deployment Tools. All other stuff you can uncheck.

To create bootable ISO image, I enter cmd.exe and there execute:

> CD "C:\Program Files (x86)\Windows Kits\8.1\Assessment and Deployment Kit\Deployment Tools\x86\Oscdimg"
> OSCDIMG.EXE -u1 -bC:\Windows81\boot\ C:\Windows81 D:\Windows81.iso
OSCDIMG 2.56 CD-ROM and DVD-ROM Premastering Utility
Copyright (C) Microsoft, 1993-2012. All rights reserved.
Licensed only for producing Microsoft authorized content.
Scanning source tree (2000 files in 803 directories)
Scanning source tree complete (2094 files in 867 directories)
Computing directory information complete
Image file is 3984359424 bytes
Writing 2094 files in 867 directories to D:\Windows81.iso
100% complete
Final image file is 3990419456 bytes

This will create bootable Windows81.iso image in a root directory of your second drive. If you have a single drive, place file into a subdirectory. Otherwise file will be written in Virtual store (usually at %USERPROFILE%\AppData\Local\VirtualStore).

Finally we have image that will not ask you for key during install and it will allow you to skip key entry for 30 days. Just burn it to CD or make bootable USB and you are ready to go.

PS: This also means that you can use your Windows 8 key to activate Windows 8.1 after installation is done. While Windows 8 key won't work during installation, it will work nicely once everything is fully installed.

PPS: If you omit EditionID from ei.cfg, you will get an option to select edition that you would like (Professional or Core).

PPPS: No, this is not a hack. Microsoft has it all documented (both ei.cfg and oscdimg.exe).

[2013-10-20: You can download ISO directly from Microsoft (see instructions at SuperSite).]

64 thoughts to “Installing Windows 8.1 (Or 8) Without a Product Key”

  1. Simply use default windows 8.1 pro generic keys XXXXX-XXXXX-XXXXX-XXXXX-XXXXX or if it did not work find other generic keys from google or

    1. Those are not generic but pirated keys. And they will stop working and Windows will definitely complain after install. Why would you go through that whey you can use key belonging to you?

      1. Sorry Josip medved but your method to skip button was not simple. I Tried your method but fail to do so. After that i found pirated keys method that works fine. After installation just use other pirated keys from net and activate through skype.

      2. I think he means using those “generic” Windows 8.1 keys to install, then after installation, you can change it to your own 8.0 key then activate it. Unless I’m not aware whether this works or not.

        Not that I condone such action Medved, but using some random key just to bypass the mandatory key step is also not so bad when you’re in a pinch and don’t have that bootable USB you carefully and lovingly prepared for such scenario.

        Thanks for the procedure and invaluable contribution Medved, I gonna try in the next days!

      1. i have downloaded windows bt i have no product key for windows 8.1 can anyone help me plzzz

  2. Worked like a charm. A lot of people have been trying to solve this problem. You rule!

  3. if your going to do USB install just copy the ISO to the usb drive with the Windows 7 USB Tool & then just go into the source folder and add the ei.cfg file

    no need to create the ISO

    1. Actually, there is a valid need for manual ISO creation.Windows 7 USB tool cannot create USB drive compatible with UEFI boot.

      If you want to use UEFI, you must create USB drive manually.

  4. I need help. How do I use the ISO to upgrade to Windows 8.1? Whenever I use the ISO, it always prompts for a Windows 8.1 key? I can’t see an option to just upgrade to 8.1. Thanks!

  5. Having many difficulties getting that to work.

    Installed windows 8.1 by the virtual store. Installed that windows dev kit. Punch in that command in the prompt and it is a no-go.

    I receive error 3……can not find specified file.

    Unable to create iso image or even find that actual directory

    “OSCDIMG.EXE -u1 -bC:\Windows81\boot\ C:\Windows81 D:\Windows81.iso”

    1. Do you have drive D?
      If not just create directory in C root, e.g. C:\Test and execute:
      OSCDIMG.EXE -u1 -bC:\Windows81\boot\ C:\Windows81 C:\Test\Windows81.iso

  6. Hello. I have a question to ask you.

    Regarding your CMD command — second line in:

    OSCDIMG.EXE -u1 -bC:\Windows81\boot\ C:\Windows81 D:\Windows81.iso

    …the last drive (D:) — what is this ISO file from???

    I also see in the process by Windows 8.1 ADK Deployment Tools, the resulting bootable Windows 8.1 ISO is beging saved at drive E as shown:

    Writing 2094 files in 867 directories to E:\Windows81.iso

    How did that happen??? What did you do on your end to accomplish that?

    Please reply with answers to these two questions, so I can make the appropriate setting on my end to achieve the end results you did.

    Thank you!

    1. Ignore E:\Windows81.iso – I have CDROM on drive D: and I forgot to adjust copy/paste – it is fixed now.

      ISO on drive D is one that you are trying to create. OSCDIMG.EXE will create it. It doesn’t exist before that step.

      If you don’t have second drive, you can create C:\Test and then execute:
      OSCDIMG.EXE -u1 -bC:\Windows81\boot\ C:\Windows81 C:\Test\Windows81.iso

      1. @ Josip Medved:

        Thank you very much! It worked great for me! I now love to have that “trial” period in Windows 8 I had with Windows 7 again WITHOUT BEING FORCED to enter my product key UPON install!

        I am wondering if and when Windows 8.2 comes out (IF that is what Microsoft does unless it goes directly to Windows 9 next time around — I am hearing rumors Windows 8.2 will be coming out mid-2014.) if the rest of the Windows 8 ‘series’ (Best word to use. We cannot call them Windows “service packs” anymore since Windows 7.) that this same technique or process you have outlined here along with Paul Thurrott’s webpage you give will also work with them too (as long as Microsoft is willing to give us the download for that particular Windows 8 series)? I am thinking it will too.

        Thanks again!

  7. Didn’t work for me. Installed without a key just fine, but when I come to activate Windows it just rejects my Windows 8 key.

  8. after realizing that your command line referred to an x86 frame rather than my 64 bit i redirected my pathway to amd section and that took care of everything. just got done installing, cd key, and updating without a hitch. nice work dude. thanks for the info.

  9. I need your help im running windows 7 home primium and i want to updgrade to windows 8.1 .I have downloaded windows 8.1 setup , windows setupbox and also windows 7 usb dvd bootable tool .Here is my promblem when i run windows 8.1 setup and input my product key XXXXX-XXXXX-XXXXX-XXXXX-XXXXX which i obtained at v-pistolero blog and it checks out correct after clicking next windows will tell me to wait and then it says windows 8.1 is not available for online purchase in your country / religion. I dont now what to do guyz please help i realy need windows 8.1. Please

  10. I tried both leaving the “[EditionID]” blank, and removing it entirely. The ISO/DVD still installs Windows 8.1 Professional automatically…

    Also, I thought I double checked, but on the x86 ISO i still saved the ef.cfg as ef.cfg.txt the first round, so make sure you save it as “All Files” in notepad lmao!

    For the people having problems, if your running the 32 bit version of windows, don’t forget to change the commands/directories!
    “C:\Program Files (x86)\Windows Kits\8.1\Assessment and Deployment Kit\Deployment Tools\x86\Oscdimg””
    would be:
    “C:\Program Files\Windows Kits\8.1\Assessment and Deployment Kit\Deployment Tools\x86\Oscdimg””

    …Even though I couldn’t make a multi-edition DVD, the “Skip” key DID work…Thank You!

  11. What if my windows 8 pro key is an upgrade. Will the install allow the option to “upgrade” if it detects windows, and will that activate me properly so I don’t have to call Microsoft to activate by phone?

    1. I have a Windows 8 Pro upgrade key as well. What do we put in the “Channel” part so this will work for us?


  12. or we could just upgrade to windows 8.1 from store it is available in it for free

    1. Upgrading is fine if you have working Windows 8 system and it is not too “dirty”. Call me traditionalist but I treat every new Windows version as an opportunity to clean the machine and start from scratch.

      PS: Assuming that you have a valid Windows 8 key, this procedure is also free and legal.

    2. Not always
      There’s still thousands out there affected by the mysterious 80240031 error that Microsoft can’t even figure out, forcing us to find alternative methods to keeping up to date

  13. When i put the ei.cfg file on the stick windows complains that no valid key was supplied for the images loaded – anyone else have this issue – is there a workaround?


  14. Nice guide!!
    If you were to use this on a oem licens, should you replace “retail” with oem??

      1. Tried playing around with it by myself… It seems that you can write anything, seemed to work with “Cock” aswell :D ? What does this do??

        I would also like to add that if you’re using a USB key to install from, you dont need all your steps. Just simply put the iso on the USB-key with “Windows 7 USB/DVD download tool”, and then create the ei.cfg file and put it in the sources folder on the created USB-key.

        1. Well, when you download the W8.1 via the SuperSite method it will ask you in the which way will you install. And one of the ways is “Install by creating a media”, which then offers you to make a bootable USB stick. So close the window, do the Josip Medved thing – create the proper “ei.cfg”. When the ei.cfg is in place, find a shortcut “Install Windows” on your desktop and then select “Install by creating a media” and then USB Flash drive (or ISO if you need one).

  15. Just played around with it by myself… It seems that you can write anything, seemed to work with “Cock” aswell :D ? What does this do??

  16. Does this generate the x86 install ISO? I noticed you are using the x86 directory. Would I need to substitue the amd64 path to generate a 64 bit install?

    Scott Emick

    1. Assessment and Deployment Kit is (mostly) 32-bit and that is reason why it is in Program Files (x86). Regardless of that, it works for both x86 and x64 installations.

      1. What Scott is trying to ask is, if I need a windows 8.1 64-bit ISO do I need to change the directory to amd64 instead of x86:
        Do I need to replace
        CD “C:\Program Files (x86)\Windows Kits\8.1\Assessment and Deployment Kit\Deployment Tools\x86\Oscdimg”
        CD “C:\Program Files (x86)\Windows Kits\8.1\Assessment and Deployment Kit\Deployment Tools\amd64\Oscdimg”
        if I need a 64 bit installer?


  17. i tried the 2 step and created ei.cfg and pasted in the source folder then started the setup it shows — some thing happened–
    setup has failed to validate the product key.

    I updated my 1st pc with store and copied all the downloaded file in usb now when i installing on second pc it shows the above error.

    Help me out.

  18. First of all i downloaded the Windows 8.1 n also installed it… But how do i start i dont understand which files have be copied and where to… can you please Help

  19. Thanks a lot! This is going to help me perform a Windows 8.1 100% clean install without having to install “8.0” first. I’d just like to point out that it’s very easy to generate and edit an ISO if you have proper software. In my case, I have UltraISO (but there are many other similar programs), which can extract the image from a CD or DVD, bootable part and all, and allows me to edit it at will and save it back. It can also extract the bootable binaries from a boot disk and save them for future use. Much better, faster and easier than using OSCDIMG. Such programs are paid, but not expensive, and well worth every cent – they are extremely useful.

    From the ISO, a USB stick can be easily generated, if one prefers so (although in my experience, the difference in the lengthy file copy stage is not that great, compared to the DVD), with the Windows 7 USB-DVD Tool, which can still be downloaded from Microsoft and several file repositories. In spite of the “Windows 7” name, it works with all Windows versions from XP to 8.1.

  20. If you want a boot DVD for BIOS and UEFI-based computers then use this command:

    Oscdimg -bootdata:2#p0,e,,e,bEfisys.bin -u1 -udfver102 C:\win8.1\media C:\win8.1\win8.1×64.iso

  21. OSCDIMG.EXE -bootdata:2#p0,e,bC:\Windows81\boot\,e,bC:\Windows81\efi\microsoft\boot\efisys.bin -u1 -udfver102 C:\Windows81\ D:\Windows81.iso

  22. Hi,

    I downloaded the windows 8.1 using one of the trick available on Internet. But my windows 8pro key is not working. Hot solve this.

  23. i have a problem an eror code 0xc004c003.Can somebody help me too fix it ,thanks……

  24. I install windows 8.1 pro but need to activation key I have key but it is not working please help me

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