Recently I was trying to load a solution source controlled by TFS but some projects in that solution were not being loaded in solution explorer inside visual studio. After spending hours of my time, for temporary reason when I deleted the whole "Global Section" at the end of .sln (solution file) by manually editing it in a notepad and restarted Visual Studio, all projects appeared as expected. I am using VS 2008. It hasn't shown any odd behavior yet, but couldn't understand the reason.
Does "Global Section" in solution file play and important role? Any harm in removing global section?
Well, you just deleted any source control bindings, plus build configuration and some solution-specific settings.
VS should revert to defaults if it doesn't find the section, though I suppose it would have been better if you knew just what was causing the issue. If the problem was with TFS then maybe resetting that fixed the problem.
As to harm, again, if VS is able to cope with the removal of the section and can revert to defaults then I see no harm. Of course you might lose configuration information, which will have to be re-applied.