Will it be possible to upgrade from Windows 8 Release Preview to the RTM version?
I've seen this related question Upgrade/Update Windows 8 customer preview to normal version, but I'm interested to know if I will be able to upgrade from the Release Preview to the final Release To Manufacture version.
Microsoft had already announced that there would be no upgrade path from the Release Preview to the RTM version of Windows 8, and for whatever reason you'd still want to be able to do this, it appears it's now possible with an easy (unsupported) workaround.
A blogger over on the Knowledge Exchange posted the details on how to fool the RTM to allow the upgrading of the Release Preview and earlier versions of Windows 8 as far back as the Developer Preview. This trick should work on any version of a test Windows 8 build anyway.
Simply find the n:\sources\cversion.ini file on the media and open it with notepad. Change the two numbers from 8508 to 7100 save and close the file.
You need to put your extracted ISO / installation in a place you can make changes to it to edit this file. In short, in a writable disk.
Note : This is purely a Workaround
upgrade is limited to transfering your user files which is 100% more then what was possible when you upgraded from Windows 7 RC to the RTM version Windows 7.
You might be able to but I would not rely on it. The Windows 8 FAQ mentions upgrading from previous versions but does not specify upgrading to the final released version. I know in previous releases it was not an option. At the end of the day you should treat it like beta software and not depend on it working.
According to an MS MVP's in a thread on answers.microsoft.com:
...note that the final release of Windows 8 will not support upgrading from any prior Windows 8 "Preview" release, though the migrate option will still be supported.
More information on the "migration" option from Paul Thurrott's Win SuperSite. There are four possible choices for Windows 8 upgrade and from the Release Preview and only the minimal migration of personal files is supported. Applications will need to be reinstalled. And I agree with his closing comments:
Should you take advantage of this feature? Honestly, if you’re using a Microsoft account to sync settings already, and have configured the SkyDrive desktop application to reconfigure your Windows 8 libraries already and store important documents and other data files in the cloud, you may be better off just doing a clean install. Of course, you perform either of these install types at your own risk, and be sure to back everything up ahead of time either way.
It may be possible with some "hack", but it is not officially supported. However, it IS possible to do a "custom" install of Windows 8 RTM (even using upgrade media) if you have a previous Windows 8 Release Preview installation on your computer. It will place your old files in a folder called "windows.old" at the root of your main drive (I have done this). Your programs and settings will NOT be preserved and you will need to re-install them.
