(No actual programming involved, hence posting here instead of SO.)
A couple of days ago I installed Visual Studio 2010 beta 2 on freshly installed Windows 7 box. This has never had VS2010 beta 1 installed.
I've just checked out my code from Subversion (which was last run in VS2010 beta 1), and tried double-clicking on the solution file - nothing happens. The icon shows the VS2010 infinity band, but hovering over it shows Version: (unrecognised version).
I can open up the solution manually, but why does Explorer not know about the version? (Which I assume is why it won't open up via double-clicking.)
EDIT: I've just checked against a solution created directly in Visual Studio 2010 - and that one works! I've had a look in the files themselves, and I can't see any obvious differences... will keep experimenting.