Importing non-UE C++ classes

I am new to UE. I follow tutorials and be able to create new C++ classes in UE4.

But I try to import my C++ classes from other non-UE projects and failed.

What I done

  1. Add those classes via IDE (Visual Studio Community 2015)
  2. Rebuild solution (compile success)
  3. Close VS 2015
  4. Close UE Editor

The UE launcher cannot open that uproject. It got crashed without errors.
Can anyone please help? I need appropiate steps to do that. Thanks

You can run the uproject from command line and print some logs by “UE4Editor.exe your.uproject -game -log”, or write the logs to some file by “UE4Editor.exe your.uproject -game LOG=somefile.txt”.