Downgrade From Windows 7 Ultimate To Professional Or Home Premium Edition Using Windows 7 Downgrader

If you have ever tried to downgrade from a higher edition of Windows 7 to a lower edition, you probably know that reinstalling the Windows 7 with the desired edition is the only way to do it. You get only Upgrade option during the installation process.

Windows 7 Downgrader

Windows 7 users who would like to downgrade from Ultimate or Enterprise edition to Professional or Home Premium edition can use an excellent portable application called Windows 7 Downgrader that helps you downgrade from a higher edition to lower edition easily.


The Downgrader does the job by changing some registry values. Of course, you will need to go through some installation procedure to make it happen. The advantage of using this tool and method is that you will not loose your data or installed programs.



1. Download the Windows 7 Downgrader tool and run with admin privilege. Click the edition that you want to downgrade to and close the application.


2. Put the Windows 7 installation DVD into the drive and run the setup (.exe) file (don’t boot using the DVD). During installation, select the edition that you want to install (downgrade) and then select Upgrade (it’s actually downgrade option) option.


3. Follow the usual Windows 7 installation procedure to complete the downgrade process.


You might also like to know how to downgrade from Windows 7 to XP and Windows 7 to Vista.



  1. Uday says

    I’ve tried to downgrade from Enterprise edition to professional using this procedure but facing same problems as Larry.

  2. Kingsley says

    It seems that SP1 conflict with this hack. So you need to uninstall SP1 first. But in my case, I installed from a DVD of Windows-7 that already included SP1, so I cannot uninstall SP1. I will have to bite the bullet and reinstall everything.

  3. Jon says

    I got that error message to start with, but once I unzipped the exe and ran it as an administrator, it made the changes and the “upgrade” worked fine

  4. Larry says

    I’ve tried a dozen different iterations of this process — manually changed registry entries for product/edition, ran program as user and as administrator, etc. I have licensed Win7 Pro & Home Premium and am trying to downgrade from Enterprise. But the downgrader program always produces the following error message. Is there a simple fix?? Hoping you can help. THANKS!!
    Unhandled exception has occurred in your application….

    Access to the registry key
    ‘HKEY_LOAL_MACHINE\SOFTWARE\Microstof\Windows NT\Curent Version’ is denied.

    See the end of this message for details on invoking
    just-in-time (JIT) debugging instead of this dialog box.

    ************** Exception Text **************
    System.UnauthorizedAccessException: Access to the registry key ‘HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion’ is denied.
    at Microsoft.Win32.RegistryKey.Win32Error(Int32 errorCode, String str)
    at Microsoft.Win32.RegistryKey.CreateSubKey(String subkey, RegistryKeyPermissionCheck permissionCheck, RegistrySecurity registrySecurity)
    at Microsoft.Win32.Registry.SetValue(String keyName, String valueName, Object value, RegistryValueKind valueKind)
    at Windows_7_Downgrader.Form1.Button3_Click(Object sender, EventArgs e)
    at System.Windows.Forms.Control.OnClick(EventArgs e)
    at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
    at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
    at System.Windows.Forms.Control.WndProc(Message& m)
    at System.Windows.Forms.ButtonBase.WndProc(Message& m)
    at System.Windows.Forms.Button.WndProc(Message& m)
    at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
    at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

    ************** Loaded Assemblies **************
    Assembly Version:
    Win32 Version: 2.0.50727.5446 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v2.0.50727/mscorlib.dll
    Windows 7 Downgrader
    Assembly Version:
    Win32 Version:
    CodeBase: file:///C:/Users/Larry/Downloads/Windows%207%20Downgrader.exe
    Assembly Version:
    Win32 Version: 8.0.50727.5420 (Win7SP1.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/Microsoft.VisualBasic/
    Assembly Version:
    Win32 Version: 2.0.50727.5447 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System/
    Assembly Version:
    Win32 Version: 2.0.50727.5446 (Win7SP1GDR.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Windows.Forms/
    Assembly Version:
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Drawing/
    Assembly Version:
    Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
    CodeBase: file:///C:/Windows/assembly/GAC_MSIL/System.Runtime.Remoting/

  5. jone says

    I face the error message “bad image” when i run windows professional cd exe. any idea to solve this problem?

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