How to Upgrade Windows 7 Beta To Windows 7 RC1 Without Formatting Your Hard Disk

Microsoft released the Windows 7 Release Candidate for public testing early this week. If you have not grab your copy, you can download it at the Microsoft download site.

This time round, Microsoft is offering the download at least through July 2009, so there is no need to rush for it.

If you are currently Vista on your computer, you can easily upgrade to Windows 7 RC 1 without reformatting the hard disk. However, if you have already converted fully to Windows 7 since beta release, you are out of luck, because Microsoft does not allow you to to perform a direct upgrade from the Beta.


We’ve also learned that many of you (millions) are running Windows 7 Beta full time. You’re anxious for a refresh. You’ve installed all your applications. You’ve configured and customized the system. You would love to get the RC and quickly upgrade to it from Beta. The RC, however, is about getting breadth coverage to validate the product in real-world scenarios. 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. We know that means reinstalling, recustomizing, reconfiguring, and so on.  That is a real pain.  The reality is that 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.

Excerpted from MSDN blog

If you decide to follow Microsoft’s advice and do a clean installation, you can use the Windows Easy Transfer application to back up/restore your data easily. However if you are looking for a quick fix to upgrade to Windows 7 RC 1 directly from Beta, here’s the hack:

1. Download the Windows 7 RC1 iso file.

2. Download and install Virtual CloneDrive in your Windows 7 beta. You should see a new virtual drive in your Windows Explorer.

3. Right click on the virtual drive and select VirtualCloneDrive -> Mount. Navigate to the location where you save the RC1 iso file and select the file. This will mount the iso in your system.

win7-mount-iso

4. Open the virtual drive (right click and select Open, do not double click). Copy all the files to a new folder in your hard disk (or a flash drive).

5. In the new folder where you have saved all the files, browse to the sources directory. Open the file cversion.ini with Notepad.

6. Change the MinClient build number to 7000

win7-modify-cversion

7. Save the file in place with the same name.

8. Go up one folder and double click the Setup file to start the RC1 installation.

win7-installation

That’s it.

Note: You might experience some oddity with this method of upgrading. For best user experience, it is advisable to do a clean installation.