How to Upgrade Your Windows 7 Test Version to the Final Release

Starting August 6th, Windows 7 is available through several official channels such as TechNet and MSDN. People who already use test versions of Windows 7 will want to grab their own copy as soon as possible and upgrade their systems. By default, the Windows 7 DVD setup allows you to upgrade only from Windows Vista or Windows XP, not from a test version of Windows 7. To help you out, I created this guide on how to upgrade from your current test version to the final version of Windows 7. As you will see, the procedure involves a very simple tweak of the normal installation procedure.
NOTE: Depending on the test version you are upgrading from, this procedure is prone to failure. Before you try to do this, make sure your data is properly backed up. In case of issues you will have to make a fresh installation.
Also, this procedure works only if you upgrade to the final version of Windows 7 Ultimate. Upgrades to other versions are not supported.

Tweaking the Windows 7 Setup Files

First, you need to have a DVD with the Windows 7 setup available. If you have an ISO image of it, you can burn it on a DVD using the Windows Discs Image Burning application included in Windows 7 or you can mount it using a tool such as Daemon Tools or Virtual CloneDrive.
NOTE: To make sure everything goes well, make sure that you have at least 16 GB of free space on your Windows 7 'C:' drive. That's the recommended requirement for the upgrading process.
Now, insert the Windows 7 DVD in the DVD-ROM unit, or mount the image, and click on the 'Open folder to view files' option, when the AutoPlay window opens. If AutoPlay is disabled, start Windows Explorer and open the contents of the DVD.


Create a new folder on any of your partitions and copy all the content from the Windows 7 DVD to that folder. Then, remove the Windows 7 DVD from the DVD-ROM.

Open the folder you just created and search in the Sources folder for a file named cversion.ini.

Open the cversion.ini file and modify the MinClient field number to 7100 or the test version of Windows 7 you are upgrading from. If you don't know your current test version, it is written on your desktop in the bottom-right corner.
By changing the number from the MinClient field, you are bypassing the version checking process of Windows 7, so that the upgrade from your test version will work.

Save the file and run the setup.exe file from the folder where you stored it.

After you receive an UAC prompt, you will see the Windows 7 setup window. Click on the Install now button from the installation window.
Windows will copy some temporary files needed for the upgrade and it will ask if you want to download the latest updates and hardware drivers. Click on the option that you want and proceed to the next step.

Next you will see the license terms of Windows 7. Read the terms and check the 'I accept the license terms' option. Then click on the Next button.
Now you can choose from two installation options: custom or upgrade. Click on the Upgrade button.

Windows will check the compatibility of the hardware and software that you have installed on your system with the new operating system version. If any incompatibilities are encountered, you will see a list which contains all of them and you will have to decide if you want to continue the upgrading process or not. In this case I recommend you to exit the upgrading process, uninstall the software applications that are not compatible with the new version of Windows 7, search for compatible hardware drivers and only then try again to upgrade Windows 7.
Depending on your choice, click on Next or close the installation window to cancel the upgrading process.
If you clicked on the Next button, the upgrading process will begin. Windows will restart automatically several times before it finishes. The whole upgrading process should not take more than one hour to complete.

After the upgrading process finishes most settings will remain intact and you can continue using your PC without any issues.

Conclusion

Unfortunately this procedure can be prone to failure in certain cases. We've tried this on two PCs with two different test versions installed and, on one of them, the upgrade process worked without errors but, once installed, Windows 7 did not function very well. In such a scenario, the best solution is to format the partition where you installed your current version of Windows 7 and make a clean installation. If you have some good tips on how to make this upgrade work flawlessly, don't hesitate to share them.