Can’t open a solution? Check your line endings

I’ve run into this issue occasionally over the past few months, but just wrote it off as a minor annoyance.  There are some Visual Studio solutions that wouldn’t open when I’d double-click on them.  Nothing would happen at all.  I’d have to open Visual Studio first, then open the solution from there.  I also noticed that the icon of the file didn’t have the little “10” in the corner:

Bad solution

The issue cropped up again this week, and also happened to a coworker, so I decided to dig into the solution file itself to find out what was wrong.  That’s when I noticed the file had Unix line endings (\n) instead of Windows line endings (\r\n).  Correcting the line endings fixed the file and now the icon looked right:

Good solution

The strange part was other guys in the office had no trouble opening the solution, so why didn’t it work for me?  I figured the “10” in the icon must have something to do with it, and noticed I still had Visual Studio 2008 installed.  I’m guessing this issue happens if you have two versions installed and the file gets opened through the Visual Studio Version Selector.  That can’t seem to handle files with incorrect line endings.

OpenWithVersionSelector

At least this reminded me to finally uninstall Visual Studio 2008.  It makes me a little sad.  That one performed so much better than 2010.