What you need to know about the Windows 7 Release Candidate

Microsoft has finished its work on the Windows 7 Release Candidate and has announced a distribution schedule. For those who are thinking of evaluating this release, I’ve put together this FAQ.
Written by Ed Bott, Senior Contributing Editor

Updated 5-May

Microsoft has finished its work on the Windows 7 Release Candidate and has announced a distribution schedule. For those who are thinking of evaluating this release, I’ve put together this FAQ. If you have any additional questions, ask them in the Talkback section; I'll update this post as needed.

What is the Windows 7 Release Candidate?

The Release Candidate (RC for short) is the most recent milestone build in the Windows 7 development process. The official build string is 7100.0.090421-1700. It is available in x86 and x64 formats.

Update 5-May: The Release Candidate code is available for update here.

Will there be additional release candidates after this one?

That’s not in the plan of record, and it’s unlikely to happen. Interim builds will be prepared between now and the final release for testing internally at Microsoft and externally by OEM partners. But this is the final version that will be made publicly available before Windows 7 is released for manufacturing and sent to retail channels and OEM partners.

Is the Release Candidate feature-complete?

Yes. Rumors that Microsoft is holding back a secret feature or radical change in the Windows 7 user interface are unfounded. Although it's possible that Microsoft will add some new desktop backgrounds or screen savers, what you see in the Release Candidate is what you'll get when the product is released. Microsoft's work from now until then is in fixing the last round of bugs, most of which will be related to OEM configurations and hardware support.

Back in early March, I spotlighted some of the visual changes in Windows 7 that you'll see in the Release Candidate (see "A sneak peek at the Windows 7 Release Candidate"). In addition, Microsoft has announced that it will release a custom version of Virtual PC with a licensed copy of Windows XP SP3 and make the combination available as a download for licensed users of the business editions of Windows 7 (Professional and up). This add-on, called Windows XP Mode) will not be included with the release candidate, nor will it be part of the final RTM product. 

What's changed from the beta release?

A lot, actually. See my review "Windows 7: What to expect" and the accompanying screenshot gallery for more details. 

Will the RC be available to the general public?

Yes. Just as with the beta release, the public will be able to download and install this release for evaluation purposes.

Do I have to pay anything to use the Windows 7 RC?


When will the RC be officially available for download?

Participants in the technical beta program got access to the RC bits on April 30, as did TechNet and MSDN subscribers. You can sign in using your credentials and download the RC code from those sites. The public download site went live on May 4.

What format will the download be available in?

Downloads will be disk images in ISO format, which can be burned to DVD. You can also mount the file to a virtual drive using a program like Virtual Clone Drive. Your CD/DVD burning program may offer this capability as well.

Can I install the Windows 7 release candidate over an earlier beta release?

That depends. If you use the setup files as distributed, you will be blocked from upgrading over any build prior to 7077. That includes the beta release (build 7000) and most leaked interim builds from April 4 or earlier. There is a workaround, however, which I'll document in a follow-up post.

Can I upgrade my existing copy of Windows XP?

No. The XP-to-7 upgrade path is not officially supported. Microsoft has advanced deployment tools to assist with XP migrations in enterprise settings, but for the RC you’re better off using the Windows Easy Transfer utility to copy your data and settings to external storage, then restore it (and reinstall your programs) after performing a clean install of Windows 7.

Can I upgrade my existing copy of Windows Vista?

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Yes, with some caveats. First, you must have Windows Vista Service Pack 1 installed; the original (RTM) release of Vista can’t be upgraded. In addition, you can upgrade only within the same processor family: Vista x86 to Windows 7 x86, and Vista x64 to Windows 7 x64. You cannot upgrade an x86 machine to x64 or vice-versa. An upgrade installation preserves user accounts and passwords, Windows settings, installed programs, and data files but might replace some device-specific drivers with generic Windows 7 versions. In my tests, Vista upgrades have worked very well across the board. That’s not surprising, given that Windows 7 is based on the same core platform and the same driver model as Windows Vista.

Can I install Windows 7 in a virtual machine?

Virtual machines have their uses, and all of the virtualization platforms I looked at currently support Windows 7 as a guest OS. One major caveat is that virtualized hardware does not offer support for Aero graphics and thus doesn’t give a true picture of the desktop experience. VMs also don’t support direct connections to some hardware devices such as TV tuners. VMs are ideal for testing software compatibility and creating simulated networks.

Can I install Windows 7 on an external USB or IEEE 1394 (FireWire) hard drive?

No. Windows 7 cannot be installed on any drive that Windows identifies as removable. Depending on how your system is configured you might be able to install the OS on an eSATA drive, which appears to the operating system as an internal fixed drive.

Can I choose which edition to install?

The release candidate image is configured to install Windows 7 Ultimate Edition. If you want to choose a different edition, copy the installation files to a different location, delete the Ei.cfg file from the Sources folder, and then run setup from that location. 

Will Windows 7 work with my software? 

That’s one big reason to evaluate this release, isn’t it? Most mainstream business and entertainment programs that work on Windows Vista will also work on Windows 7. Programs that are likely to fail (at least until patches are available) are system utilities that interact with hardware at a low level, such as disk defragmenters, and some security software. If you run Windows 7 Setup from an existing copy of Windows Vista and choose the upgrade option, you’ll get a report listing any known incompatibilities.

Where can I find Windows 7 hardware drivers?

The drivers included with the Windows 7 RC cover a very wide range of devices, and others are available through Windows Update. If you find that a particular device isn’t supported, you should be able to use the Windows Vista driver, although you might have to jump through some hoops to bypass compatibility checks. Some vendors have released beta versions of Windows 7 drivers. Both Nvidia and ATI, for example, have released WDDM 1.1 video drivers for Windows 7. Creative Labs has released Windows 7 drivers for some devices and has announced a release schedule for others.

How long does installation take?

That depends on your hardware and the installation type. A clean installation on a fast desktop system should finish in a half-hour or less. On slower hardware, it could take up to an hour. When performing an upgrade, you'll need to allow additional time for migrating data files and settings. I haven't seen any upgrade take more than two hours.

Do I need a product key?

Technically, no. At the end of the installation process you’ll be prompted to enter a product key. If you leave this box blank, setup will continue and your copy of Windows 7 will work with no restrictions. You will have to enter a valid product key before activating.

I have a product key from the Windows 7 beta. Can I use it on the Windows 7 RC?

Yes, in my testing product keys acquired as part of the beta program work just fine for clean installs and upgrades. Update 5-May: Microsoft says, " Previously issued Product Keys for the Windows 7 Beta are not intended for continued use, we are recommending that you register and get a new Product Key for the Windows 7 RC."

Do I have to activate my installation?

By default, Windows 7 will activate automatically three days after you install it. You can disable automatic activation during setup by clearing the check box below the product key box. If you do not activate at the end of the 30-day grace period, you can continue to use the RC, but you’ll have to put up with nag screens and a forced black background. You can reset the 30-day grace period up to four times, using the same technique that works with Windows Vista.

How long can I use the Release Candidate?

The software will stop working on March 1, 2010, which should be long after the official release is available. You must either uninstall the RC or replace it with a licensed copy of the final RTM code before then.

When will Windows 7 be released to manufacturing?

Your guess is as good as mine. In the words of a Microsoft executive, "Those who know, won't say. Those who say, don't know."

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