Is Windows 7 RC the same as build 7077?

The Windows 7 Release Candidate is complete. It’s currently being unofficially distributed on BitTorrent networks, and the official release has begun as well. Technical beta testers, MSDN/TechNet subscribers, and the general public (in that order) will be allowed access to Microsoft-run download servers in waves between now and May 5.

I have a copy of the RC code, obtained through official channels, and I’m spending this weekend in a flurry of upgrades and clean installs. I’ll be sharing details and lessons learned from my experience over the next few days and weeks, mostly at ZDNet.


Based on my initial experience, though, I think I can solve one mystery. It’s not one of the great riddles of the ages, but I’ve been curious to know which of the 70xx builds wound up being declared the official release candidate and recompiled into build 7100. I think the answer is 7077.

I found the best clue is in the Sources folder on the installation media. The file Cversion.ini determines whether upgrades are allowed or blocked from the current build. The settings in the official release are as follows:


If you try to use this media to upgrade a system running the December Beta release (build 7000), you’ll be blocked unless you edit this file. You’ll also be blocked if you try to upgrade from most of the interim builds (7022, 7048, 7057, 7068) that found their way onto BitTorrent sites in the past few months.

But if you’ve been running build 7077 or later, the upgrade will complete without any problems. I can’t say for sure, but that suggests to me that the underlying code is identical and that the only change is the date stamp and the build number.

Update: Several Microsoft insiders have made it pretty clear to me that there were indeed significant “iterations” in the code base between 7077 (April 4) and 7100 (April 22). Thanks for the correction.

If you’re already running 7077, you don’t need to jump through any hoops to upgrade to the RC when it’s available. You can run Setup directly over that installation and it will work just fine.

10 thoughts on “Is Windows 7 RC the same as build 7077?

  1. The underlying code is by no means identical. All of the time and builds spent between 7077 and 7100 were for bugfixes.

    It’s highly recommended that people upgrade, Ed 😛

  2. 7088 was bumped to 7100, meaning 7088 and 7100 are identical, but there are still differences (mainly stability fixes) between 7077 and 7100.

  3. You seem completely out of the loop Ed or that was huge jump to conclusion. Should we all still be skeptical of the XPM as well? 😉

    1. I find it amusing that you chose to use a different name for this comment than you normally use, “Solomon.” Why is that?

      And I never said anyone should be “skeptical” of the XP Mode coverage. I said, and I quote, that “The fact that this add-on isn’t available in the RC suggests it’s still under development and you should be skeptical of any reports you read now.” The only hands-on reports I’ve seen are from Rafael Rivera, who acknowledges that he’s working with very early code that doesn’t even use the correct name of the feature. So I’ll withhold judgment on this feature until I actually see something for myself that looks like it’s close to a finished product.

  4. Whats the point in running tests if you’re not going to change code?

    “Update: Several Microsoft insiders have made it pretty clear to me that there were indeed significant “iterations” in the code base between 7077 (April 4) and 7100 (April 22). Thanks for the correction.”

    I can appreciate you wanting to make interesting posts. But you just made the bit about “identical code” up, and it was completely wrong. I also have an official copy of RC1, and am unsure how you thought it was “exactly the same”. It’s fairly obviously different.

    1. The point in running tests is to ensure that you haven’t had any regressions.

      I have had it confirmed that there are no, repeat no, visible differences between 7077 and 7100. It’s not “fairly obviously different” and in fact I am told by a high-level source that the changes made amounted to 10 or fewer bug fixes.

  5. I downloaded Windows 7 RC on May 6. I just checked the Cversion.ini file and here’s the results:


    What the…?

    1. Yes, that’s basically where they cut off the upgrade ability, meaning that you can safely upgrade 7077 to RC.

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