I was happily using VS2010 Premium version for a C/C++ coding project, and needed to add the C# components (long, irrelevant explanation on that). When I tried to go back and open up my existing C/C++ solution, i received the following VS2010 error: cannot open projectName.vcxproj because "it is not supported by this version of the application." Any ideas ?
I went back to repair/reinstall VS2010, and discovered the error: When I added the C# component, I did not want to re-download all of the other components already installed. But by leaving those items unchecked, apparently they were uninstalled, or at least made inaccessible. There is also the possibility that those components remained, and a switch exists to turn them back on, but if so that has eluded me.