This is about how to Reset or Remove Windows Activation/Remove license key using a command. It will work for window operating system all versions. This is very important for any admin to make sure before formatting any of system remove license which exist in the systems or activated the same.

If we are a formatting system or removing before the license, it may cause you to activate the system back with same License key. Like if we are using OEM OR Multiple activation keys and doing above without following the same. We will be getting an error like “you have reached multiple activation limits” or “Unable to activate the windows with entered key.”

See below URL for activation issue error code and details:,-in-windows-server-2008,-and-in-windows-vista


So below are the steps to remove activation key from the system:

  • Log in to the system with admin account and open CMD with Run as admin rights.
  • slmgr /upk It stands for uninstall product key. The /upk parameter uninstalls the product key of the current Windows edition. Once this command will execute we need to restart, the system will be in an Unlicensed state unless a new product key is installed.

  • Enter slmgr /upk and Hit enter then wait for this to complete. This will uninstall the current product key from Windows and will move windows to unlicensed mode.  

  • The /cpky option removes the product key from the registry to prevent this key from being stolen or taken by malevolent code.

  • Now enter slmgr /cpky and hit Enter then wait for this to complete. Once this command will execute, this will remove the product key from the registry if it's still there. Below is the screen shot for the same result would be on the screen:  

  • Move to the next Enter slmgr /rearm and wait for this to complete. This is to reset the Windows activation timers so the new users will be prompted to activate Windows when they put in the key.  

  • Once all done above, we can see our Windows actvation properties status as not available.