Engineering Windows 7

Welcome to our blog dedicated to the engineering of Microsoft Windows 7

Delivering a quality upgrade experience

Delivering a quality upgrade experience

This is a little bit of a tricky post to write because we’re going to be asking everyone using our Windows 7 Beta to help us out, but doing so is going to take a little time and require a bit of a commitment to helping test the next milestone. This has been a remarkably valuable and beneficial testing cycle for Windows as we have had a tremendous amount of very rigorous testing and usage. We’ve had millions of people install and use the Beta since January and as we’ve talked about, the feedback and telemetry have been of tremendous value as we finalize the product. The effort of Beta testers has contributed immensely to our ability to deliver a high-quality product to hundreds of millions of customers. We continue to follow the plan we have previously outlined and this post is no announcement of any news or change in plans. Since we know many people are running the Beta we want to provide a heads up regarding the behavior of the Release Candidate (RC) as it pertains to upgrades. Of course we are working hard on the RC and following the schedule we have set out for ourselves.

A big part of the beta process is making sure we get as much “real world” coverage of scenarios and experiences as possible and monitor the telemetry of those experience overall. One of the most challenging areas to engineer is the process of upgrading one release of Windows to another. When you think about it, it is the one place where at one time we need to run a ton of code to basically “know” everything about a system before performing the upgrade. During the development of Windows 7 we routinely test hundreds of original OEM images from Windows Vista and upgrade them and then run automated tests validating the upgrade’s success. We also test thousands of applications and many thousands of devices as they too move through the upgrade process.

Many of you installed the Windows 7 beta on a PC running Vista. We received that telemetry and acted on it accordingly. We believe we’ve continued to improve the upgrade experience throughout the release. Similarly, based on our telemetry most of you did clean installations onto new drive partitions. Through this telemetry we learned about the device ecosystem and what drivers were available or missing. We also learned about PC-specific functions that required installing a driver / application (from XP or Vista) to enable support for buttons, connectors, or other hardware components. Together we get great coverage of the setup experience.

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. During development we introduce changes in the product (under the hood) that aren’t always compatible with what we call “build-to-build” upgrade.  The supported upgrade scenario is from Windows Vista to Windows 7. Before you go jump to the comment section, we want to say we are going to provide a mechanism for you to use if you absolutely require this upgrade.  As an extended member of the development team and a participant in the Beta program that has helped us so much, we want to ask that you experience real-world setup and provide us real-world telemetry.

If you do follow the steps below, you might run across some oddities after upgrade. We experience these internally at Microsoft occasionally but we don’t always track them down and fix them because they take time away from bugs that would not only manifest themselves during this one-time pre-release operation. From time to time we’ve noticed on a few blogs that people are using builds that we have not officially released and complained of “instabilities” after upgrade. Nearly all of these have been these build-to-build issues. We’ve seen people talk about how a messenger client stopped working, a printer or device “disappears”, or start menu shortcuts are duplicated. These are often harmless and worst case often involves reinstalling the software or device.

We’re just trying to be deterministic and engineer the product for the real world. Speaking of the real world, many have asked about upgrading from Windows XP. There's no change here to the plan as has been discussed on many forums.  We realized at the start of this project that the “upgrade” from XP would not be an experience we think would yield the best results. There are simply too many changes in how PCs have been configured (applets, hardware support, driver model, etc.) that having all of that support carry forth to Windows 7 would not be nearly as high quality as a clean install. This is something many of you know and already practice. We do provide support for moving files and settings and will prompt at setup time, but applications will need to be reinstalled. We know that for a set of customers this tradeoff seems less than perfect, but we think the upfront time is well worth it.

So when you try to upgrade a pre-RC build you will find that you’re not able to and setup will tell you and you can then exit gracefully. You can install as a clean installation and use the Windows Easy Transfer feature as well (run this from your current installation of course) if you wish to move your accounts, settings, files, and more. To bypass the version check, the instructions below will use a mechanism that is available for enterprise customers (so we are also testing this as well). It is not a simple command line switch. We didn’t make it multi-step on purpose but wanted to stick to using proven, documented and tested mechanisms.

These instructions will be brief. Since everyone reading is a well-versed and experienced beta tester you know ALWAYS BACK UP YOUR MACHINE before running any OS installation and NEVER TEST AN OS ON YOUR ONLY COPY OF ANY DATA. Testing a pre-release product means just that—it is testing and it is pre-release. Even though this is a Release Candidate, we are still testing the product. We have very high confidence but even if an error happens once in 1,000,000 we want to make sure everyone is taking the precautions normal for a pre-release product.

One other related caution is INSTALL ONLY OFFICIALLY RELEASED BUILDS FROM MICROSOFT. It will always be tempting to get the build with the “mod” already done but you really never know what else has been done to the build. There’s a thrill in getting the latest, we know, but that also comes with risks that can’t even be quantified. For the RC we will work to release a hash or some other way to validate the build, but the best way is to always download directly from Microsoft.

Here’s what you can do to bypass the check for pre-release upgrade IF YOU REALLY REALLY NEED TO:

  1. Download the ISO as you did previously and burn the ISO to a DVD.
  2. Copy the whole image to a storage location you wish to run the upgrade from (a bootable flash drive or a directory on any partition on the machine running the pre-release build).
  3. Browse to the sources directory.
  4. Open the file cversion.ini in a text editor like Notepad.
  5. Modify the MinClient build number to a value lower than the down-level build. For example, change 7100 to 7000 (pictured below).
  6. Save the file in place with the same name.
  7. Run setup like you would normally from this modified copy of the image and the version check will be bypassed.


These same steps will be required as we transition from the RC milestone to the RTM milestone.

Again, we know many people (including tens of thousands at Microsoft) are relying on the pre-release builds of Windows 7 for mission critical and daily work, making this step less than convenient. We’re working hard to provide the highest quality release we can and so we’d like to make sure for this final phase of testing we’re supporting the most real world scenarios possible, which incremental build to build upgrades are not. At the same time everyone on the beta has been so great we wanted to make sure we at least offered an opportunity to make your own expert and informed choice about how to handle the upgrade.

We’re always humbled by the excitement around the releases and by the support and enthusiasm from those that choose to run our pre-releases. We’re incredibly appreciative of the time and effort you put into doing so. In return we hope we are providing you with a great release to work with at each stage of the evolution of the product. Our next stop is the RC…see you there!


--Windows 7 Team

PS: At Step 1 above many of you are probably thinking, “hey why don’t you just let me mount the ISO and skip the plastic disc”. We’ve heard this feedback and we deserve the feedback. We don’t have this feature in Windows 7 and we should have. So please don’t fill the comments with this request. There are several third party tools for mounting and if you’ve got a Vista image there’s a good chance your PC came with those tools on it.

Leave a Comment
  • Please add 4 and 2 and type the answer here:
  • Post
  • Excuse Team, this Update is from Vista?

  • Hi team. I have been trying some of the other builds out, but have now almost copied this before you even posted it. I reverted to Vista Home premium (factory install) and then re-installed an upgrade to Windows 7 build 7000 in anticapation of the RC1 when its released. That means I am now back with IE8 crashing nearly all the time when trying to access some of my favourite websites.

    This was actually one of the reasons why I tried one of the 'unofficial' builds as it is fixed in those, so I wait with baited breath for the RC1 to be lauched so that I can then surf with no problems!

    Keep up the good work Windows 7 team, you are doing a great job, oh and thanks for listening.

  • Indeed - this ought to be standard functionality in Windows now (it's that useful).  I'd love to not have to both installing third party tools to unpack/install a MS product!

  • Sounds reasonable enough, it's Beta for a reason so why waste time on an upgrade path.

    I hope in the RC that pinned items are at the bottom of the list rather than the top, who's idea was it to put your pinned items at the furthest point possible from the clicking point!!?

  • So Build 7100 will be RC1?

    Im sry to use leaked versions of Windows 7...but after use the Beta for over 1 and a half month i cant find more problems and switch over to a leaked version becouse i use 7 as a primary OS...

  • Just would to ask you...doas Microsoft lissen to: ?

  • Mounting ISO, try the free tool Virtual Clone Drive.

  • Nice, TY :D

  • I just wanted to thank you guys for being so open and involved in the beta/RC program. It's awesome, and quite a deviation from previous Windows beta programs. It's also a bit surprising that you guys aren't absolutely furious about all the leaks, but I guess that's just more real world testing. Can't wait for the RC, and the RTM.

  • I'm eager for the Release Candidate as well, and I hope you've monitored that website - they've noted some inconsistencies in wording and icon styling, and how some things, like Task Manager and Windows Defender, which could use the now in-icon progress indicator ability of Windows 7.  I hope more programs make use of that excellent at-a-glance functionality.

    I hope Win7 can bring improved podcast support to WMP and WMC, and that the improvements to Win7 will continue past RTM.  Looking to the future, I hope that the first Service Pack will bring a host of new features that you wanted in RTM but couldn't put in there due to time constraints.

    Keep up the good work!

  • Well, i'm still using XP because you (microsoft) leave me no other choice. I happen to have converted my system disk to a dynamic disk, and by doing so, and the crap support from windows vista , and now windows 7, i won't be able to install any other OS ever, considering i'm not about to loose everthing else on this disk. How about some dynamic disk support!!!!!!!!!!!!

  • I only do clean installs. But I hope the telemetry from my computers and notebooks is usefule nonetheless.

  • I challenge the Windows 7 team to write a blog entry without using the words "Ecosystem", "Experience" or any other over used buzzwords.

  • @schwarz

    Just curious, what feature of dynamic disks do you depend upon? And, since XP to Windows 7 isn't a supported upgrade, you can always use Windows Easy Transfer(WET or Migwiz) from the Windows 7 DVD to copy your data off to an external location & then clean install Windows 7 using WET to restore your data.

  • I haven't upgraded a Microsoft OS since Windows 98. Its is just a given when switching to a new version of Windows that a complete whipe and fresh install is the only way to avoid broken software, performance loss and funky crash states and or obscure error messages.

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