Sometimes, for unknown reasons, VS 2008 creates solution files led by a newline.
Microsoft Visual Studio Solution File, Format Version 10.00
# Visual Studio 2008
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This happened on various machines, and I have no idea why this is. A Google search did not yield any useful results.
Now, why do I worry about this? Because I can't open these solutions in Windows Explorer. I have to open VS, select File - Open - Solution and it works fine. But to open solutions from within Explorer, I have to edit the sln file and remove the leading newline.
Edit: After Leom's suggestion I tested a few times and found that the issue is solely dependent on the leading newline.