Upgrade Windows 7 RC Ultimate to Windows 7 RTM Enterprise

We all know that Microsoft doesn’t technically support to upgrade from Windows 7 RC ultimate to Windows 7 RTM Enterprise since there’s no in-place upgrade found in Windows 7 RC Ultimate, but doesn’t mean it’s impossible or it can’t be done at all. Here the solution....

Do a little change inside your Windows 7 Ultimate:

• Navigate to Registry Editor : Start > Run > Regedit
• Head to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\Current Version you can see its location in the following image:

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• Change Ultimate with Enterprise in ProductName and EditionID. You’re done modifying Windows 7 RC.

Afterward you must do the following in order to bypass the check for the pre-release upgrade:

1. Take the Windows 7 Enterprise DVD and create an ISO image. open the ISO afterward modify a file, more specifically, cversion.ini.
2. After you own ISO image, use an ISO image editor (you can try PowerISO), and browse the DVD image. Locate \sources\cversion.ini and extract it to your desktop, then open it with notepad.
3. Change the winclient value to 7100, save and close.(winclient=7100)
4. Replace the file in the ISO with the file you just edited and burn the ISO to a DVD.
5. Start the installer from within Windows.