I want to install Windows 7 RC. I know about the time bomb in June of 2010, where it will cease to work, and that a few months before that it will shut down every two hours.

If I install Windows 7 RC, will I be able to upgrade it to a non-time bombed version? If I pre-order the RTM, will I need to wipe clean and do a fresh install when it is released?


I installed Windows 7 RTM on my wife's laptop, upgrading from Vista Ultimate x64 with no problems. Had to uninstall Daemon Tools & ATI Catalyst Control Center first though. I decided not to install the RC first, since I have access to the Technet download on Aug 6.

  • Awesome that this question was mentioned on the StackOverflow podcast, sorry my answer is the official MS standpoint and not the good work around Joel linked to. Commented Sep 16, 2009 at 12:46

10 Answers 10


Brandon LeBlanc on this Windows 7 Team blog post states you need to do clean install from the RC versions.

Brandon is the Windows Communications Manager at Microsoft

  • in that blog post, Brandon says they expect the RTM in the latter half of July. I think I'll just wait for the RTM version. Commented Jul 15, 2009 at 14:27
  • The offiical release date for Windows 7 is October 22. The RTM in July is for MSDN and TechNet subscribers. Commented Jul 16, 2009 at 22:56
  • 1
    I've personally done this on my laptop and it went just fine. It takes longer than a "clean" install, but afterwards all my stuff was there, and it all worked. That's what I cared about, so I was very pleased.
    – Mark Allen
    Commented Aug 6, 2009 at 20:02
  • 1
    Upgrades from RC to RTM are not supported. You may get lucky.
    – Greg D
    Commented Aug 6, 2009 at 20:32
  • 3
    You can actually tweak a file to make the upgrade work. See PhantomTypist's answer below for an illustrated guide, otherwise Joel's link is roughly the same thing. Commented Aug 7, 2009 at 15:35

There is a technique described here which sounds like it might work to upgrade RC->RTM. Has anybody tried this?

  • 2
    I used it successfully to upgrade from the last beta to the RC, so i'm certainly gonna try... once i have access to the RTM version.
    – Shog9
    Commented Aug 2, 2009 at 0:37
  • 3
    FWIW, i tried it... for now at least, it appears to have worked just fine.
    – Shog9
    Commented Aug 7, 2009 at 3:47
  • 2
    It worked in my machine Commented Aug 8, 2009 at 21:41
  • 3
    It works on my 3 machines. Commented Aug 17, 2009 at 14:34
  • It worked for me upgrading from build 7200. Yay!
    – RedFilter
    Commented Aug 20, 2009 at 18:11

The How-To Geek has a write-up on exactly how to perform an upgrade from RC to RTM.

How to Upgrade the Windows 7 RC to RTM (Final Release) :: the How-To Geek

EDIT: FYI, in the linked article the How-To Geek explains exactly what build number you must specify in the cversion.ini file to make this way of upgrading work.

  • 1
    The same technique was also linked in a couple of answers above, though I went for the walk-through approach to make it easy to understand. Commented Aug 7, 2009 at 15:23
  • Yeah, thank you for doing that. I was unsure about the needed MinClient build number needed.
    – 410
    Commented Aug 7, 2009 at 15:24

Yes, but there's a catch. The "upgrade" is really a custom install that will leave your current Windows 7 RC install intact.

However, you will not be able to do an upgrade installation, in which your existing programs and data are left in place. Instead, you'll have to do what Microsoft calls a custom installation. This is essentially a clean install, but your existing operating system, programs and data are squirreled away in a folder labeled WINDOWS.OLD. You end up with a fresh Windows 7 setup, but you can access that folder to get to any needed data. (Sorry, the programs in there won't work - you'll need to reinstall them.)

Here's the full article.

  • 1
    Note this is not the case when you use the method of editing CVersion.ini. All my programs and data were preserved and ready to go.
    – RedFilter
    Commented Aug 20, 2009 at 18:13

Here is how:

  1. Download the RTM ISO.
  2. Copy that burnt image to a temp folder
  3. Find the Sources directory in the temp folder, and open the file CVersion.ini in your favorite text editor
  4. Modify the MinClient option to 7000 (from 7233.0)
  5. Save the file, and then run setup as normal to start installation.

Works in my machine

Original from LifeHacker
Slightly modified to match the exact steps I take to do it.

Note: This is essentially the same as Joel's answer
More: Super complete guide with pictures at HowToGeek.com

Important Notice

The Windows 7 beta or RC releases were Ultimate edition, so you’ll only be able to upgrade to the RTM (final) if you are installing Ultimate Edition. (from HowToGeek.com)

  • This is essentially the same as joel's answer, just copied localy Commented Aug 7, 2009 at 19:15
  • @Andrew: you are right. Added note to the post Commented Aug 8, 2009 at 21:43
  • 3
    the 'important notice' part can be avoided with registry tweaking like described here for vista: dltv.wordpress.com/2007/05/30/… i've done upgrade from RC ultimate to RTM enterprise using this technique, i can confirm it works
    – zappan
    Commented Aug 9, 2009 at 11:58

It seems to be working per Sam Gentile using technique described here.


Yes, and no. You can keep your existing install, but it will be moved to a Windows.old folder.

See Engadget:

Users running an activated version of Windows 7 Release Candidate will not have to "reinstall an older version of Windows before using a Windows 7 upgrade disk." Unfortunately, those who choose this path will see all of their files and such ushered into a folder labeled "Windows.old" when the final version of Win7 is installed

  • Right - you won't have to wipe your computer clean, but you will have to do a fresh install (your old install will, as joshunt said, be saved in "Windows.old").
    – Keithius
    Commented Jul 15, 2009 at 12:48

When my copy of the Beta expired, it started BSODing with an expiration reason. Now that's an effective way to enforce it :)


See this FAQ by Ed Bott


GA isn't until October 22, not the latter half of July.

The current rumor is that you will in fact be able to upgrade, however until the final product ships there's no way to be sure.

Upgrading may simply be as easy as editing one config file on the DVD (instructions), then installing from there. I did it from the Beta to the RC without issue.

  • 1
    I have access to Technet, so I'm able to download RTM even as I type this. Commented Aug 6, 2009 at 21:50
  • 1
    Public release isn't until October 22, 2009. The RTM has already happened. MSDN and Technet subscribers got it August 6, 2009. OEMs got it even earlier (within the last week or three).
    – raven
    Commented Aug 7, 2009 at 21:25
  • -1 for wrong RTM date
    – RedFilter
    Commented Aug 20, 2009 at 18:17
  • Correct, I meant GA isn't until October 22. RTM happened already.
    – mrdenny
    Commented Aug 21, 2009 at 4:27

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