After upgrading MSVC2015 to Update3, I had the same problem: instead of std::map in the Watch window display as a horrible std::_Tree<std::_Tmap_traits... etc., some plugins started to throw exceptions, some projects was not able to run in debug mode.
All was solved by deleting CurrentSettings.vssettings. It is usually located at Documents\Visual Studio 2015\Settings If not, go to `Tools -> Options -> Environment -> Import and Export Settings ‘ to find the location of this file.