Probable Fix: Problem in Activating Windows 8 After Clean Install

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In my last post I showed you how to download a bootable Windows 8 Pro ISO file and use it to make a clean install. However, since it’s an upgrade license, you can only install Windows 8 as an upgrade over your existing Windows OS and some users might experience difficulty activating the license online while following this process.

If you are having difficulties in activating, here’s a workaround proposed on Ghacks that might help in activating Windows 8. I am not entirely sure how well it’d work out but let’s try it out, you have nothing to lose anyways.

Note: This involves playing with the Windows Registry so proceed with caution, and at your own risk.

Fixing Windows 8 Activation

Step 1: After installing Windows 8, press open Run box (Windows+R), type in regedit and press enter.

regedit run box

Step 2: Windows will ask for admin privileges to run the tool and open Windows Registry Editor once you confirm. In the Registry Editor navigate to HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Setup/OOBE/ and look for the key MediaBootInstall.

Regedit navigate

Step 3: Double click on MediaBootInstall and change the value from 1 to 0. If you don’t see the key, create a new 32-bit DWord and provide the values.

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MediaBootInstall dword

Step 4: Having done that, exit the Registry Editor and run the command prompt as an administrator using Windows 8 Start Screen. Search for CMD, right-click on the tile and select the option, Run as administrator.

run command prompt as admin

Step 5: Execute the command slmgr /rearm and restart the computer when Windows prompts you to.


Finally, after restarting Windows, open your system properties and try to activate Windows 8 again. Most probably you will be successful this time. In the process you will be asked to enter Windows 8 Product Key again.



Again, as the title of this article said, this is a probable fix and I am not 100% sure if it works. You can go ahead and give it a shot. Don’t forget to share your results and the problems you came across (if any) while applying the fix. Other readers might be interested in that. I personally tried the fix and it worked but I did an upgrade and not a clean installation.

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Show archived comments (34)

Archived Comments

  1. KrudoManic says:

    Thank you, I was wondering if there was a way in which this could be done. very easy fix and one which we shouldn’t have to do in the first place. You should never upgrade from one OS to another. Clean install is the best way.Why…? Well there are to major factors when upgrading and OS. First of all the CAB and WinSock files can become corrupt and then you would either run SFC if this failed you’d have to reinstall the main OS and then the upgrade again.

    Clean install of your entire OS is much better and reliable. I don’t understand why MS decided on allowing a clean install but if you tried to register you OS it wouldn’t let you. WTF… What planet was they on when they decided on this. All experienced and advanced users such as myself, all know you should always perform a clean install of a new OS. Start with a clean slate always.

    Thank for the tip AWESOME

    • CaptnSam says:

      Worked like a charm. Had to change value from 0 to 1 though. Spent the better part of an hour with microsoft customer support trying to activate (no success) before trying this.

  2. TZ says:

    Yep! worked brilliantly!

  3. DJE says:

    Tried it, and it worked just fine. Thanks so much for posting this solution.

  4. Kent says:

    Saved my rear! –THANKS!
    The command is “slmgr -rearm” and NOT a ‘/’.
    ALSO be sure that you are in “C:windowssystem32”
    Thanks again!

  5. Ravikumar.R says:

    Hi Thanks…

    I have tried its not working…..

    its giving error “Error code 0xc00400c3

    Error description The activation server dertermined the specified product key has been Blocked

  6. Win8 Pro from Zero says:

    Took a different approach. Blank brand new SSD hard drive, Windows 8 Pro box set. Installed Win8 Pro , try to activate, get Error code 0xC004F061, must be upgraded from…Etc. Install disc in drive install Win8 Pro again, (chose to save nothing, whatever ) installs over itself and activates this time. Yes!! Restart with install disc still in, boot from the disc, delete the SSD hard drive entire contents. Install Win8 Pro for the third time. Installs and is activated. Worked on both of my computers. Purchased 2 box sets for $69.99 each.
    Since then have activated, on both, my free Windows Media Center upgrades that I received by applying on Microsofts website. Hurry expires on Jan 31 2013.

    • muffinfaceEarth says:

      I’ve done something similar, with the retail disk installed first, then installed the upgrade (Yes I upgraded windows 8 pro with…windows 8 pro) and it updated. I decided I needed a true clean install so I tried installing just the retail disk. To my surprise, it shows that my upgrade key is valid. Not sure why though

  7. Verkade says:

    Not sure what this does, but it worked wonderfully!

  8. nice fix!!

  9. Alan says:

    Worked very well without any troubles, even on a windows 8 installed on a mac. Thank you very much.

  10. This did not work for me sadly. I have Windows 8 Pro, purchased through Micrsoft’s website and upgraded my PC and had a HDD failure and lost all my data. I booted this up and activated it on a new SSD I purchased, the key will not activate Windows due to the face that the activation server reported that the product key has exceeded its unlock limit. I have only installed this on 1 PC but had upgraded the motherboard, CPU, PSU, RAM, but kept the drives and kept the GPU.

  11. NG says:

    Perfect instructions. slmgr /rearm is the right code and it did work. After restart, windows not activated message disappreared.
    Thanks Ashish – keep up the good work. Thanks for sharing

  12. walid says:

    great work thanks alot it works for me

  13. Tom says:

    I appreciate your help – but – do you really tested it? I tried and directly after I used this workaround, rebooted my system and tried to activate – i get another error message saying: The activation server reported that the Multiple Activation Key has exceeded its limit. (Error code 0xC004C020).

    And you know, I wouldn’t said a word against it, if they had told me, that that rubbish I buy is _only_ an upgrade. It’s not written on the package! And the salesman even corrected me saying that it is a real, valid full OS, not an upgrade.. Gosh …. Micro$oft

  14. Ketobbey Waters says:

    Perfect. The command is “slmgr -rearm” and NOT a ‘/’. ALSO be sure that you are in “C:windowssystem32”
    Worked very well. I used this after I could not get “ACTIVATE BY PHONE” to show up for me to call them… 😀 I love this!!!!
    Thanks Kent and thanks to the author!

  15. Sandeep Gulati says:

    Thanks… good one. It works for me…:) also for the command slmgr /rearm – syntax is correct.

    At the end after rebooting the PC it asked me phone window where you have to call to customer support and after telling system generated digits they will provide their digits which you need to enter in activation screen.

  16. no-stress. says:

    hi, just tried this fix and it worked. laptop originally came with windows 7, i purchaed the upgrade to windows 8 when windows came out (first month after W8 came out MS had a very good discount) unfortunately my SSD drive crashed, and i just installed a new SSD and installed windows 8 without installing windows 7 first. i had this problem and this solution fixed it, thanks…

  17. affy says:

    works like a charm. tqvm

  18. himanshu jain says:

    in MediaBootInstall it is already 0 value..what to do now ?? :(

  19. Dawn Marie says:

    Worked perfectly! Thank you.

  20. Scott says:

    Last post was 10 months ago, but I just want to confirm that this work around still functions. Thank you!

  21. onthemovefit says:

    Thanks a TON!

  22. Amar says:

    Can it be written with the name “SetupDisplayedProductKey” instead of “MediaBootInstall”? Please help!

  23. Asif Ali says:

    You can also Read Related below Post..

    Window 8 Product Keys List 100% Working – Visit Below Post Link

  24. Anders Hegrestad says:

    I love you, no homo!

  25. nick says:

    great job. many kisses from Greece. It really worked, i cant believe it.

  26. Max Roszell says:

    I don’t have Mediabootinstall!???

    • Greg says:

      Did you read ?
      It says :
      Step 3: Double click on MediaBootInstall and change the value from 1 to 0. {{{{If you don’t see the key, create a new 32-bit DWord and provide the values.}}}}}

  27. PALOHAN says:

    did this today, on a clean 8.1. Had to create that registry key. Rebooted. It ate my product key, even thanked me => THIS IS REALLY LEGIT

  28. Matthew says:

    Worked perfectly!! Thanks for the info!

  29. Shane Johnson says:

    THanks a Ton! I have had to do this process twice in the last few days due to Hard Driver failure. quick and easy and I really really enjoy not having to contact MS phone support. Great Job!