One of the nice things to come out of Microsoft’s complete overhaul of the Windows installer for Vista and beyond was that it did away with the idea that different variations of Windows needed different discs. Previously each distribution of XP (Home/Pro/MCE) required its own disc, and then each license type (OEM/Retail/VLK) also required its own disc. This lead to an astounding number of disc types, and complete and utter frustration when for users attempting to install Windows and not having the correct disc to go with the key they had.
With Vista’s image based installer, we saw Microsoft consolidate all of this – one disc could contain every distribution of Windows, allowing a user to always be able to install Windows with any Windows disc, regardless of what their key was. This greatly simplified the installation process, resolving one of the most frustrating things about installing Windows XP.
So imagine our surprise when we’re taking a look at our TechNet copies of Windows 7 and find that there’s a different installation disc for each distribution of Windows. With the version of the Windows installer that comes with Win7, there is a new file at /Sources/ei.cfg that tells the Windows installer what OS it should install. Here’s what the file looks like from the ultimate disc:


When the Windows installer sees this file, it becomes keyed to whatever distribution the file specifies. In this case with an Ultimate disc, we cannot install Home Premium or Professional. We have not yet had a chance to test OEM and retail keys since we don’t have both, however it certainly looks like the installer is going to make a distinction there too.
Perhaps the most interesting bit of this is that the installation process itself hasn’t changed – the Windows installer still supports One Disc to Rule Them All operation, and the Windows image that comes with Ultimate for example has absolutely no problem installing lesser versions. In fact if you remove ei.cfg so that the Windows installer is not told to install a specific version, it will revert to One Disc mode. The distinction between discs is entirely trivial, dictated by a single 51 byte configuration file. You can have a One Disc installer, Microsoft just don’t want it to be the default action for some reason.
Now to be fair, this didn’t entirely catch us off-guard. We first saw this file and its functionality with the Win7 Beta, but until now we did not know if this was something that was specific to the testing versions of Win7, or if it was going to be pushed out in to retail with this limitation. Now we know our answer.
The biggest downer though is that this file is fairly tricky to remove. For copies of Windows packed in ISO files or burnt to discs, this requires remastering the ISO/disc in order to maintain its bootability – it’s not possible to just copy the contents to a new file/disc sans ei.cfg and have a One Disc. Building a proper bootable ISO/disc is still more of a dark art than a science. Users looking to install Windows from a USB flash drive will have an easier time – since installers set up on those types of drives are rewritable it’s easy to remove the offending file. Though this may not be the case with officially distributed flash drives should Microsoft go ahead and distribute Win7 that way, as rumors suggest they will.
In any case this is a significantly disappointing action coming from Microsoft. The One Disc returned the sanity to installing Windows, and made having so many distributions more bearable. Now as far as pressed media is concerned, we’re back to the dark ages of Windows XP (I guess Microsoft really was trying to copy everything about XP?). Geeks would be well advised to burn a copy of Windows 7 with One Disc capabilities as soon as they have it – if the experience is anything like Vista then the benefits will quickly make themselves apparent.
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  • Jovec - Saturday, August 8, 2009 - link

    I'm sure this decision comes from Microsoft's Vista experience of users not entering their key during setup, choosing the wrong version, and then being forced to either reinstall the correct one when they try to activate or upgrade to Ultimate to keep their installation.

  • jigglywiggly - Saturday, August 8, 2009 - link

    I got my Windows 7 disc just today from Technet! Such a money saver, I have server 2k3 enterprise, 2k8 enterprise, r2 as well, so many pcs with office 2007 on them... Yeah I love technet. I get my server 2008 r2 on August 14nth as well.
  • mmatis - Friday, August 7, 2009 - link

    a good reason to not install Windows 7. Continue to ride out with XP, and transition over to Linux instead.
  • larson0699 - Sunday, August 9, 2009 - link


    Get real. I nLited XP just the way I want it, but even I'm upgrading to 7. Which version I install is the least of my concerns; there is every reason to use the new system.

    And dude, this article was about how to get the old unified installer back, which anyone with an imaging program and DVD burner can manage. It's worth the extra half a minute IMO. You should try 7 before you settle on the idea that Linux has all your bases covered. Myself, I'm trying to switch from Linux to BSD, though I dislike having to learn new commands. Realistically, I may well end up using both in virtual machines through Windows 7.
  • overcast - Friday, August 7, 2009 - link

    Buahahahah Linux. Give me a break, you people have been saying Linux is going to take over the desktop for the past 20 years. Give it up, it's no where near user friendly, nor does it have the developer/application/game support.

  • daniel142005 - Saturday, August 8, 2009 - link

    The above poster is right. Seriously though, your using this as an excuse to not use Windows 7? Well first, XP is worse... considering you will have to have multiple disks for multiple versions anyway. As for Linux, it's at least 5 times more complicated to get linux installed and ready to do what you want (assuming you do more than just browse the web).

    This change makes PERFECT sense. When you buy the ultimate disk, you should have to install ultimate. However, the tech savvy users that actually need a disk that can install everything can still get one (and it wouldn't surprise me if they made a version downloadable for msdn customers).
  • mmatis - Sunday, August 9, 2009 - link

    I've already got enough XP discs to install whatever works with the key that my "user" has. When they hose their system with Online Poker or Free Pron or... and ask me to fix it, if they've got a legal key I've got a way to install XP. And XP works fine for most of what they want to do. And quite frankly, Ubuntu also works fine and installs VERY easily on every system I've had to mess with. Which is why I usually give them a dual-boot X and Linux. Can I make up a Windows 7 "install anything" disk? Probably. And I may end up doing that around the time Micro$oft drops SP1 for it. But I sure ain't gonna be looking forward to kissing $teve'$ butt for the opportunity to do it.
  • mmatis - Sunday, August 9, 2009 - link

    Furthermore, I haven't reinstalled Office on any of these machines in the last 3 years, and have gotten no complaints about that. OpenOffice seems to keep the users quire happy as long as you set it to default to Office formats. They can read and write everything they want, and their friends have no problem reading and writing to files they send out.
  • Mr Perfect - Friday, August 7, 2009 - link

  • Chlorus - Friday, August 7, 2009 - link

    I work at a university help desk - people need their OS reinstalled all the time. However, a large portion of those people have their keys, but are missing their disks or have damaged recovery partition. It is a nightmare, since OEM and VLK discs are constantly mixed up or are missing. This was not a problem with Vista, but it looks like MS has decided that Vista's system was too convenient.

    Now we're back to that wonderful system - going to be fun explaining this mess to clients.

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