The following texts from this post should address your concern:
When you double-click on a
.sln
file, a small program calledvslauncher.exe
is called with the path to your.sln
file as its first argument. The job ofvslauncher.exe
is to read enough of your.sln
file to determine which version of Visual Studio to use to open your file. Since you may have several versions of Visual Studio installed (VS2003, 2005, 2008, Express SKUs, etc.) you probably want to open the solution with the same copy of Visual Studio that you used to create it.Visual Studio 2008 .sln files typically start with these two lines:
Microsoft Visual Studio Solution File, Format Version 10.00
# Visual Studio 2008
That said, if your .sln file signature (the first two lines of your file) does match any known release of Visual Studio, it will be opened by that particular VS version.