Windows 8 activation error 0xc004F061 : This is an Upgrade only key

I recently purchased Windows 8 Pro activation key for 40$. Now, this being a upgrade only license, it wont activate Windows 8 in the case of a clean install. As activation service in Windows 8 looks for any traces of the previous Microsoft OS on the system, when an upgrade only key is being used. In case of a clean install, it obviously fails to find any, hence it refuses to accept your key.

So the correct* way to successfully activate your Windows 8 with the upgrade key would be to first install/have Windows 7/Vista/XP on the computer and then insert your Windows 8 Pro DVD/USB and upgrade to Windows 8 Pro. I was installing Windows 8 on my new hard drive and didn’t have the time to install Windows 7 first. Here’s what I did to activate my Windows 8 with its genuine key in the case of a clean install.

*NOTE: Only follow these steps if you have a VALID Upgrade (I.e.: You legitimately own a licence for a previous version of Windows) Else, according to DRM, it would be considered a sort of piracy.

1. Do a clean install of Windows and during the installation, skip the step of entering the licence key, else simply enter your upgrade licence key.

Widows 8 setup

Once you’re in Windows, you’re going to have to do some tweaking to “trick” it into letting you activate Windows with the Upgrade key.

2. Once you’re at your desktop, run Command Prompt as Administrator (Go to the start screen, type ‘cmd‘. You should see Command prompt on the list. Right-click it and click “Run as Administrator”. Click “Yes” on the Security Prompt).

cmd as admin

3. At the command prompt, type: regedit and press Enter.

4. Once in Registry Editor, in the registry tree, navigate to this key:


5. In that folder, look for the item MediaBootInstall. Double-click it and change the value to 0


6. Close the Registry Editor. You should still have the Command Prompt open. Now, at the Command Prompt, type the following and press enter:
slmgr /rearm

Note: The slmgr tool is discussed in detail at the end of the post.

7. It should show something that tells you the command was successful.

8. Restart the computer. Go to the Start Screen, type ‘activate’, click on the settings tab, click on ‘Windows


9. Enter your Upgrade product key and it should activate successfully!

Note: Here is a list of commonly used options along with the general syntax of the Software Licensing Management Tool (slmgr.vbs).

[tabgroup][tab title=”smlgr syntax”]


slmgr [MachineName [Username Password]] [Option]


machinename The machine to administer, by default the current local machine.

username An administrator equivalent user account for the remote computer.

password The password for the user account on the remote computer.


/ato Activate Windows license and product key against Microsoft’s server.

/atp Confirmation_ID Activate Windows with user-provided Confirmation ID

/ckms Clear the name of KMS server used to default and port to default.

/cpky Clear product key from the registry (prevents disclosure attacks)

/dli Display the current license information with activation

status and partial product key.

/dlv Verbose, similar to -dli but with more information.

/dti Display Installation ID for offline activation

/ipk Key Enter a new product key supplied as xxxxx-xxxxx-xxxxx-xxxxx-xxxxx

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/ilc License_file Install license

/rilc Re-install system license files

/rearm Reset the evaluation period/licensing status and activation state of the machine

/skms activationservername:port

Set the Volume Licensing KMS server and/or the port used for KMS activation

(where supported by your Windows edition)

/skhc Enable KMS host caching (default), this blocks the use of DNS priority and

weight after the initial discovery of a working KMS host.

If the system can no longer contact the working KMS host, discovery will be attempted again.

/ckhc Disable KMS host caching. This setting instructs the client to use DNS auto-discovery

each time it attempts KMS activation (recommended when using priority and weight)

/sai interval

Sets the interval in minutes for unactivated clients to attempt KMS connection.

The activation interval must be between 15 minutes and 30 days, although the default (2 hours)

is recommended.

The KMS client initially picks up this interval from the registry but switches to the KMS

setting after the first KMS response has been received.

/sri interval

Sets the renewal interval in minutes for activated clients to attempt KMS connection.

The renewal interval must be between 15 minutes and 30 days.

This option is set initially on both the KMS server and client sides.

The default is 10080 minutes (7 days).

/spri Set the KMS priority to normal (default).

/cpri Set the KMS priority to low.

Use this option to minimize contention from KMS in a co-hosted environment.

Note that this could lead to KMS starvation, depending on what other applications

or server roles are active. Use with care.

/sprt port

Sets the port on which the KMS host listens for client activation requests. The default TCP port is 1688.

/sdns Enable DNS publishing by the KMS host (default).

/cdns Disable DNS publishing by the KMS host.

/upk Uninstall current installed product key and return license status back to trial state.

/xpr Show the expiry date of current license (if not permanently activated)





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  1. sir
    I have a error @ slmgr /rearm
    Error:0xc004fe00 on a computer running Microsoft windows non-core edition, run ‘slui.exe 0x2a 0xc004FE00’ to display the error text

    1. I am no sir!
      The solution I posted works in the case of a clean install. Else you can always try the phone activation. It almost never fails. You really need to give me some more info, else I am just shooting in the dark. If you don’t want to try the phone activation way, the following is a possible solution: You seem to have depleted your rearm count. Reset it by deleting ‘HKEY_LOCAL_MACHINESYSTEMWPA’ Only problem is, that deleting this registry key isn’t that simple.

      Boot from your installation DVD and do the following steps:

      Press SHIFT + F10 to launch CMD as Administrator.
      Type regedit to launch Registry Ediditor.
      Select HKEY_LOCAL_MACHINE and Go to File -> Load Hive, select Computer->%windir%/system32/config/SYSTEM
      Type MY_SYSTEM as name for the hive.
      Delete WPA key under MY_SYSTEM.
      Select MY_SYSTEM, goto File -> Unload Hive.
      Exit Registry Editor.
      Exit CMD Prompt.
      Quit the Installation to reboot to your system.
      Open CMD as Administrator.
      Type slmgr -ipk
      Type slmgr -dlv

  2. It seems if you are logged into Windows 8 via an online account opposed to a local account, this fix does not work. I did the steps above twice with an online user account and it failed both times. Upon changing to a local account it worked flawlessly.

  3. Alright. THIS is what I really needed. BILLION THANKS.
    Now, in your perspective, why do you think the reinstall is blocked this way?

    1. Welcome!
      There are basically 3 types of licences for windows:

      System Builder Licence: This is the licence Microsoft expects you buy if you built your custom assembled PC and want to clean install OS onto a Windows HDD/SSD. This is the most expensive licence.

      Upgrade licence: This is when you already have a previous version of Microsoft OS installed on your PC and want to upgrade it to the latest version. In this case the OS installer looks for any trace of the old OS on the HDD/SSD. If it fails to find any trace of the old Windows OS, the activation attempt fails. The post above explains how to trick the new Windows install into thinking that an older version of windows was installed on the HDD/SSD and thereby making activation with a genuine upgrade only key work.
      Note: This should only be done if you own an older version of Windows for that PC, else it will be considered piracy. This licence is relatively quite cheap.

      OEM licence: This is the one you get when you buy a machine with Windows on it from Dell,HP,Sony,Lenovo,etc. The price of this licence is included in the price of your PC. Each manufacture usually strikes up a separate deal with MS.

      All this is done only to make money for MS. The OS is essentially the same regardless of the licence type.

  4. legend! worked a treat. had to navigate to run.exe and Run As Administrator (even though I AM admin) to make it work. thankyou!

  5. Thank you so much. I tried calling Microsoft support for this and they tried charging me over $100 to get a different technician to clean my computer because of THIS error recurring, instead of fixing the activation code like I asked. Ridiculous! With this forum’s help I was able to activate my Windows 8 just fine.
    you go, girl 😉

  6. You have no idea of the hours you have saved me… thx! I have been using Msf OS since MSDOS 3.3 and I find it very stupid to enable a person to create a DVD ISO and choose install without recovering anyting, install the OS, do the updates and then fails to activate with the legal Product Key. Very stupid decision Msf…

  7. You literally saved me HOURS having to restall Windows XP, upgrading it to SP3, then upgrading again to Win8. Not to mention the hard drive space you probably saved. Appreciate you sharing these tips!

  8. I revive an error saying, “Cannot edit MediaBootInstall: Error writing the value’s new contents.” when I try and edit the MediaBootInstall.

  9. This helped a lot. My situation was slightly different. I decided to play with VirtualBox today, and to create the first VM decided to use this W8Pro CD I have had for weeks and never installed, and keep W7 as the host OS. W8Pro installed fine in the VirtualBox, but after install, the activation process wouldn’t take the key. Just completing Two Steps aboved worked for me – the regedit and the slmgr, followed by a restart. After that, the activation key which had failed was somehow already remembered, and it self-activated without having to enter it again.

    1. Replying to myself, actually, this is a bit bizarre in my case anyway. I didn’t buy an upgrade edition, yet it kept reporting failure to activate. Still and all, I expect your little tip was the magic that somehow got it to activate. Maybe something peculiar installing into a guest VM as well.

  10. Wow, this has the potential to be incredibly useful. My computer crashed and I decided to format the drive not knowing this would create an issue with this. I am in the process of installing some other stuff and I will try it after that.

  11. So I did everything except it now says there is no activation needed, and I cant find the activation request on the applications search. So it seems the problem is gone. Or will it come back and I have to keep looking to input the code? I did input it earlier in the process … how is that going to affect this?

  12. Please help me, in the first place I do not know what it means to run it as a local or online administrator, I am trying to do this on my Mac please. But when I performed your instructions, I got this response: “Error: 0xC004F025 Access Denied. The requested action requires elevated privileges” please what does this mean? What must I do?

  13. Please let me know if you’re looking for a article writer for your weblog. You have some really good articles and I feel I would be a good asset. If you ever want to take some of the load off, I’d absolutely love to write some material for your blog in exchange
    for a link back to mine. Please send me an e-mail if interested.

  14. You are amazing. Many thousands of blessing sent your way:-)
    I had installed Windows 8 and I got this error message, then I followed your steps. It did not activate it immediately but I was able to activate it over the phone just by entering some numbers.


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