Question

There have been a ton of questions regarding upgrading all sorts of versions of Vista and 7 to different versions of Vista and 7, but I have not managed to find one with this exact issue.

I want to do an in-place upgrade of Windows Vista ULTIMATE to Windows 7 Professional. Microsoft considers this a downgrade so the installer says you must do a clean install in this case.

I am wondering if there is any way to force the installer to do the in-place upgrade anyway, similar to the tricks to upgrade RC->RTM or doing a "clean" upgrade install.

Answer 1

I don't know if the following will work :

Change:

HKEY_LOCAL_MACHINE\software\microsoft\windows nt\currentversion\EditionID = Ultimate HKEY_LOCAL_MACHINE\software\microsoft\windows nt\currentversion\productname = Windows Vista Ultimate

To:

HKEY_LOCAL_MACHINE\software\microsoft\windows nt\currentversion\EditionID = Enterprise HKEY_LOCAL_MACHINE\software\microsoft\windows nt\currentversion\productname = Windows Vista Enterprise

and do the upgrade without rebooting.

Answer 2

My impression is that Microsoft have introduced measures to resist this upgrade because the installer would not know what to do with the old Vista Ultimate stuff when it downgraded to Windows 7 professional.