Downgrade Windows 7 Ultimate to Home Premium without a clean install
Currently I've got an installation of Windows 7 Ultimate x64. I would like to downgrade to Windows 7 Home Premium x64 without a clean install. I've got a (legal) retail disc and tried the following tricks:
Trick the Windows version using a registry hack with all possible combinations
In combination with a trick to make an ISO with all editions
Still the Windows setup keeps telling me I can't upgrade because I've got a higher version installed (Ultimate). The trick seems dead. Does anyone know a way to change from Ultimate to Home Premium without the hassle of a clean install?
Windows 7 Ultimate is a superset of Home Premium, so no need exists to ever downgrade aside from licensing issues. You can change the Windows Components by going to "Start | Control Panel | Programs and Features | Turn Windows Features on or off" to remove those components included in Ultimate but not in Home Premium , effectively downgrading to the desirable version.
It is possible and I have done it. I went from x64 RC (Ultimate) to x64 Professional RTM, from there to Ultimate via Anytime Upgrade now I am back to Professional. Don't ask me why I upgraded to Ultimate in the first place
Here's how I did it: You need your RTM files with the usual suspects (ei.cfg either removed or modified with the version you want to install, in cversion.ini file the minversion edited to sth lower than the current version, i have put 7000 there). Then in the registry go to local_machine -> software -> microsoft -> windows nt -> currentversion and set currentbuild and currentbuildnumber to 7100. Replace "Ultimate" in EditionID and ProductName with "Professional" (or whatever you wanna install or the name of a SKU lower than that).
Now you can start the Win7 Setup and chose upgrade. This way it is possible to "downgrade" your version of Windows 7 without the need to reinstall everything again!
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