Upgrading Windows 7 from BETA to RC1

Having read several times now that you can’t upgrade Windows 7 from BETA to RC1, I decided it would be a good idea to post the “how-to” instructions. Obviously many people are confused here.

To upgrade from beta you need to:

  1. Extract the .iso contents 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 old build).
  2. Browse to the sources directory.
  3. Open the file cversion.ini in a text editor like Notepad.
  4. Modify the MinClient build number to a value lower than the down-level build. For example, change 7100 to 7000.
  5. Save the file in place with the same name.
  6. Run setup.exe like you would normally and the version check will be bypassed.