Microsoft has rigged the new Windows 7 Release Candidate to prevent upgrades on top of the pre-RC Beta 1 build, but there’s a work-around to save you from doing the Vista shuffle.
As Windows 7 heads towards the finish line Microsoft is busily sweeping away remnants of the beta code. This week’s Windows 7 Release Candidate, for instance, will no longer allow you to update a previous edition of the Windows 7 OS – it will install only on top of Windows Vista running SP1.
The 7RC setup routine will automatically quiet if it detects any previous build of Windows 7. This is part of edging Windows 7 towards its final form, says Microsoft.
“The RC is about getting breadth coverage to validate the product in real-world scenarios” says a post on the Engineering Windows 7 blog
. “Upgrading from one pre-release build to another is not a scenario we want to focus on because it is not something real-world customers will experience. The supported upgrade scenario is from Windows Vista to Windows 7. As a result, we want to encourage you to revert to a Vista image and upgrade or to do a clean install, rather than upgrade the existing Beta.”
However, the Microsofties realise that many current Windows 7 users won’t want to wipe their systems or reload Vista and effectively start from scratch, so they’ve shared a canny little work-around which allows you to drop RC1 on top of any previous Windows 7 build.
This relies on “a mechanism that is available for enterprise customers” the blog advises. “We didn’t make it multi-step on purpose but wanted to stick to using proven, documented and tested mechanisms.”
First up, burn the Windows 7 Release Candidate ISO image to a DVD and copy the image to the location from which you’ll run the upgrade, such as a bootable flash drive or a directory on any partition on the machine running the pre-release build.
Open the ‘sources’ directory, locate the cversion.ini file and open it in Notepad. Change the MinClient build number to a value lower than what Microsoft’s blog calls the “down-level” build – for example, change the MinClient from 7100 to 7000. Save the file in place with the same name.
When you run Windows 7’s setup routine from the parent folder this mod will ensure that the version check is skipped and the install will begin.