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.


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.

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  1. Thanks or the info, only place on the net I could find out how to do this. Thanks again!

    1. You are welcome.

  2. 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

  3. yeah, the oddity thing got me slightly worried could you elaborate further?

  4. 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. :)

  5. 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

  6. 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.

  7. 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

    1. doesnt matter i found out what i was doing wrong

      1. im having the same problem how did you fix?

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

  9. 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

  10. Yup thanks for the info it worked great.

  11. 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,


  12. This worked perfectly. Thanks to everyone who has developed and tested this solution.

  13. 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.

  14. I can’t find the cversion file? where is it?

    1. nvm i kept trying to mount the windows 7000 iso, instead of rc1 -.-

  15. Thanks! This saved me quite a bit of time.

  16. 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.

  17. 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.

  18. I cannot get virtual clone to save the new conversion.ini

    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.

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

  20. 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

  21. They havent axed it you just have to be patient

  22. 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

  23. 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?

  24. cversion.ini is a read only file and it wont let me save the new build in the folder. any help?

    1. @bob: You are still using Win 7 RC1? Go get the release version.

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