Interesting... I have Firefox 3 and Firefox 4 beta installed and working on my machine. If I don't choose to use the update and download another version I can install them side-by-side. Which makes sense. You're UPDATING existing software so it will be replaced. I think your Visual Studio is broken I have 2005, 2008 and 2010 installed and double clicking on any .sln file opens in the correct version of Visual Studio - in fact the .sln files have either an 8, 9 or 10 in the icon telling you this. I don't use the .csprj files from explorer because Visual Studio wants to make an .sln for it if you don't, so what's the point. Delphi on the other hand does not do this (I wish it did). The problem as I understand it is like this. Lets say back in the early '90's you purchased Sybase database and installed it. Then you decided to install SQL Server 6.5 and during the install or usage of SQL Server it removed Sybase. It's the same code base, but separate products. This would be wrong and I'm sure you'd be pissed just like the Original Poster. The thing for Red Gate and any other software vendor for that matter should be something like this. Inform the user. Crazy idea I know. Something like "Hey we don't play well with product X, by continuing the install we're going to remove Product X for you". Only make it show up if the installer detected product X, which it already had because it removed it anyway. In a perfect world UX should trump business decisions.