I purchased a Dell laptop with windows 8 pre-installed. Then I upgraded it to windows 8.1 by Windows App Store, everything is fine. Now accidentally I updated the product key (invalid one) and windows got deactivated. Now I want to activate the Windows 8.1, I have genuine Windows 8 OEM key (found using get_win8key program from BIOS). I don't want to Go by installing Windows 8, then upgrading it windows 8.1 then installing all my software again as suggested by Dell. As at the time of upgrade It didn't ask for product key and I assume that program read the key from BIOS itself and Windows 8.1 is activated, so there should be equivalent key to be used to activate windows 8.1 again. Please suggest.


use the command line tool slmgr.vbs to insert the key:

slmgr.vbs /ipk YOUR_OEM_KEY

Now run this command to activate Windows:

slmgr.vbs  /ato
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    This is a valid solution for windows 8, not for 8.1. I am getting following error while attempting to run first command - Error: 0xC004F069 On a computer running Microsoft Windows non-core edition, run 'slui.exe 0x2a 0xC004F069' to display the error text Feb 19 '14 at 5:32
  • 0xC004F069 = SL_E_MISMATCHED_PRODUCT_SKU This means your key doesn't work for the used SKU. Most OEMs system are the Core edition. Do you use the Pro now? Feb 19 '14 at 18:28
  • @magicandre1981 what should be done in the above case "Error: 0xC004F069 On a computer running Microsoft Windows non-core edition, run 'slui.exe 0x2a 0xC004F069' to display the error text" Apr 19 '14 at 12:20
  • this means SL_E_MISMATCHED_PRODUCT_SKU. Is your key for the same Windows Edition? Apr 20 '14 at 6:26

From our experience with Windows 8 upgrades, you're right out of luck. If your Windows 8.1 becomes inactivated for any reason, you can only use an 8.1 key to activate it. The keys are (intentionally) different and incompatible.

No, it didn't read an 8.1 key from anywhere. It just remembered it was activated and (because the Store is secure) it was allowed to stay that way. Upgrades via DVD seem to always finish up deactivated and needing a new key.

Your choices are (a) buy/acquire a new 8.1 key or (b) roundtrip through reinstalling 8 and upgrading through the Store. You can talk to Microsoft or your OEM supplier, but I wouldn't expect much help.

  • Thanx for suggestion. Feb 22 '14 at 5:04
  • This comment is not entirely true, since I was able to solve this without re-installing or contacting MS. Dec 11 '14 at 10:17
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    I you know something we don't, please feel free to explain
    – david.pfx
    Dec 11 '14 at 21:59

I have Asus Zenbook with pre-installed Windows 8 (normal, not pro). I installed clean Windows 8.1 and couldn't get it activated. It asked license key, which I didn't knew.

I was able to retrieve my licence key from BIOS (MSDM KEY) with WpKey util (pkeyui.exe). Windows 8.1 accepted this key and I was able to avoid all this "re-install Windows 8 and upgrade to 8.1".

There seems to be multiple ways of retrieving MSDM key: http://www.nextofwindows.com/how-to-retrieve-windows-8-oem-product-key-from-bios

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