After upgrading a project to newer version of Visual Studio, you might face this problem: your main form may not show up when you run the application either in debug mode or release mode.
This problem might cause because of the database connection but there will probably no error or warning. So, the trick is that:
- Go to “Project > Properties > Build“
- Change “platform target” to “x86“
- Run your application again. It will give the actual error message
- Don’t forget to change “platform target” to “Any CPU” after taking caring of the problem (If this setting is what you want)