yes, the project files for different Studio versions have different content; this is independent of the .NET version that is being targeted by the project. So VS2010 can create a project that targets .NET 2.0, and said project will result in an exe/dll that runs fine on a 2.0-only system, but the project itself won't open in VS2005. :) Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles] I only read formatted code with indentation, so please use PRE tags for code snippets. I'm not participating in frackin' Q&A, so if you want my opinion, ask away in a real forum (or on my profile page).