Quoted from IEBlog:

http://blogs.msdn.com/ie/archive/2006/11/30/ie6-and-ie7-running-on-a-single-machine.aspx#1186820

This “solution” shows the utter lack of talent at Microsoft. An application shouldn’t be so ingrained into an operating system that an entire virtual environment is needed to use different versions. I used to believe it was a pain testing web applications for quirks in IE6, Mozilla, Opera, Safari, etc, but now, thanks to the dolts at MS, I have to run a virtual environment in addition to my normal rounds of testing, and I guess I can forget about supporting IE6 users after April 1st. Because the Software Engineers at Microsoft are clearly lacking in their ability to produce a well written operating system, I’ve provided a diagram below to prevent mistakes like this from happening again, courtesy of my undergraduate OS class:

The right way to write an operating system:

[hardware]

[kernel]

[applications]

Notice how the applications sit entirely on their own level. Ingenuous!

The wrong way to write an operating system:

[hardware]

[kernel+GUI+Browser+Mr.Clippy+...]

[3rd party applications]

Notice how the applications, like Internet Explorer, are integrated with the OS. While this may be good for protecting monopolies, it’s bad for every one of your users. So please avoid it in the future!

- One unhappy customer

http://blogs.msdn.com/ie/archive/2006/11/30/ie6-and-ie7-running-on-a-single-machine.aspx#1186839

Damn, i see so many “well” trained people here. You call yourselves developers ? You are coding machines, have you ever developed something real in your life? Something that works on every noticeable browser at least on the market ? MS did a good think for themselves to keep you locked in in IE, but you see how many problems it created? I lay my hat down for IE, at the beginning of its age, it was a tool FOR developers, a tool that because of ignorance to the new wave of web features or because of too much bugfixes suddenly transformed itself in tool against developers, and i actually mean AGAINST(<-- font-weight:bold;font-size:8em;) developers, or at least good ones, that are preocupied to run their software for all of their clients. You people at MS, at least the ones that are developing IE, should make a partnership or quit doing browsers, give support to Mozilla or Opera to create a damn standards friendly browser. And create something like Apollo from Adobe for your own platform taste. IE is now a mess, progress has been made with IE7 but it is far from being or at least trying to be as standards friendly as FF or Opera or Safari. You could even start concentrating on doing good, quality software as a plugin for FF (like .net integration). Active-X is a mess. No serious company still sees it as a common choice over java(if you want low level stuff, not possible with flash). You have lost the plugin war, and the browser war is still won by you, but only by inertia. I repeat it again, i bet you have great programmers there, but because you are a company "for the money", they will always have pressure on them from above and never finish a good quality product, they will always have to switch focus on something else than browsers.Dont tell me that your browser team, in 7 years has developed only and only IE7. The so crazy "developers, developers" is something like a Jabba roar when i kill my mind hacking IE to make my client or my boss happy. And this thing of not being possible to run two versions of IE on the same machine is quite a blow. IE is only damn renderer, and i bet the part that breaks is the one that made windows so integrable with it. You've got sued for this, and you also got sued for the Eolas issue.And even your own plugin architecture got broken.We have to rely on crazy JS hacks to insert a MediaPlayer plugin, not making our content possilbe to multiple devices, or having to overwork to avoid this. Problems that the Opensource Mozilla Gecko engine will never have. I finish my rant here, but probably Adobe's Apolo will be the wave of the future with Internet Applications, or might that be ExpresionSuite with .net ? Or the browser will maintain forever its might.

http://blogs.msdn.com/ie/archive/2006/11/30/ie6-and-ie7-running-on-a-single-machine.aspx#1187334

Its funny I was just thinking about how messed up Windows had done things and how simple the logic would be. If it where me developing an OS (Which I realize is a lot of work) that I wouldnt want anyone being able to mess around with the core of the OS itself and that to create a folder like the windows folder that is not writable to period and have another folder for all 3rd party applications including there own so that the end user would have full control but not have to worry about any program / user from removing files that make the os work. you could have a layer overtop of the core os that could be modified to look like it was modified but not actually changing it so if you didnt want it you could remove it. Another method of working with IE 6 and IE 7 that no one has mentioned is to have access to another pc and using vnc or something of the like, thats what I do for all my web dev. For app dev I use vmware cause I dont want to blow up my os lol (again because its so unstable) I think developers should just say to hell with older browser versions and force an update lol if all websites wouldnt work with IE6 people would have to upgrade. Yes I realize there are cases where you cant upgrade but still (thats no excuse)