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.

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.


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


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.


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.

Damien Damien

Damien Oh started writing tech articles since 2007 and has over 10 years of experience in the tech industry. He is proficient in Windows, Linux, Mac, Android and iOS, and worked as a part time WordPress Developer. He is currently the owner and Editor-in-Chief of Make Tech Easier.


  1. This is very cool however it would be greatly appreciated if you would explain exactly what you mean when you “Note: You might experience some oddity with this method of upgrading”, as this is exactly what I want to do.
    Thank you

  2. The oddity warning is issued by Microsoft. I am still testing it out and have not encountered any oddity yet. I will update once I found some odd incidents. :)

  3. Thank you, thank you! It worked perfectly. No data loss and all programs are functioning normally. Windows Update has already done at least 4 updates. Chrome, Outlook and IE8 — no problems

  4. hey the process is either stuck or taking way too long at the part “gathering files, settings, and programs” at 0%. i had to restart it once since it was at 0% for 10min…15 at most…

    any help?

    im running ~2ghz and 2gb ram. hp laptop.

  5. every time i try and save the file it keeps saying i cannot save here or that it is a read only file, any ideas how to resolve this? thanks

  6. One note, will not work if the users, windows and program files are not on the same partition (not supported).

  7. I’ll let you know what I think. I understand perfectly the upgrade process and have quite a complicated system (RAID10, multiple partitions, quadcore, etc).

    Let’s see if I can break it ;) Thanks, -John

  8. Damien,

    This article was superb and worked perfectly. thank you very much! I’ll be sure to check back on this site regularly.

    Much appreciated,


  9. Worked fine and using Firefox after upgrade. Hopefully, everything else also works fine. took an awful lot of time, but ti did pull through in the end. Thanks a ton man. You saved me a lot of time and headache.

  10. my problem is that my PC shuts down every 2 hours, do i have enough time to do the upgrade?

    if it takes longer than 2 hours, will my computer shut down in the middle of the upgrade?
    thanks for the help

    1. I’m trying it now myself, but I’ve heard the solution to that is to set your clock back a month to some date before July 1, then do the install, then fix the clock.

  11. This method didn’t work for me. While it did prevent the error message “Can’t upgrade this version of windows” from coming up during the Checking Compatibility step, it didn’t alleviate the other error messages such as “You can’t upgrade a 32 bit to 64 bit windows version” or “You can’t upgrade a 64 bit to 32 bit version of windows”, even though I’m upgrading 64 -> 64.
    If you have the same issue, download a torrent that has a file. That did the trick for me. You can search for it at the pirate bay.

    1. Did you copy all the files in the VirtualClone Drive to a new folder in your local hard disk? You won’t be able to edit and save any files in the virtual drive.

  12. Time was running on on the beta build so I just upgraded to the RC build with this method, working great, thanks Damien.

  13. Anyone know how to upgrade RC to RTM? I used this guide to upgrade from Beat to RC but it appears Microsoft has axed this “hack” as now the “Checking Compatibility” operation cycles endlessly. Any advice would be great

  14. i downloaded an iso of windows 7 and checked the cversion.ini file and in that minclient is 7233.0 and minserver is 7100.0, in this case should i replace 7233.0 with 7000.0 or 7100.0

  15. where do i get the RC1 file? i have a Aspire One Acer mini with no CD drive at all, i have windows 7 starter, will this even work for my computer?

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