If you check the Optimize option when converting, Visual COBOL will try to minimize the number of Visual Studio project files created within a Visual Studio solution. It does this by looking at the Net Express build settings for each built file (.EXE or .DLL) and if the build settings are identical then it will add the programs to a single Visual Studio project with the type to build as multiple executable files. If these NX files do not have the same build settings, i.e. the Link to Lib field is set or the Run-time type is not set to the default NX values then it cannot combine the programs into one Visual Studio project but will instead put each program into its own project.