Upgrading Win7 beta to RC (and to RTM when it becomes available)

By tom on April 17th, 2009

Hello, as you might have read or noticed, the latest Win7 builds refuse to install if you have a previous beta build installed. The Win7 team explains in this blog post the reasons for this.

There is however a way to bypass this check (also from the blog post):

  1. Download the ISO as you did previously and burn the ISO to a DVD.
  2. Copy the whole image to a storage location you wish to run the upgrade from (a bootable flash drive or a directory on any partition on the machine running the pre-release build).
  3. Browse to the sources directory.
  4. Open the file cversion.ini in a text editor like Notepad.
  5. Modify the MinClient build number to a value lower than the down-level build. For example, change 7100 to 7000 (pictured below).
  6. Save the file in place with the same name.
  7. Run setup like you would normally from this modified copy of the image and the version check will be bypassed.

These steps will also be necessary when they transition from RC to RTM.

Hope this helps!