The project could not be compiled

Hi, I’m trying to create a new C++ project. While the project is created, it gives me the error below and asks me if I want to continue to compile on Visual Studio. When I say “Yes”, VS2013 opens and compiles the project without problem. I can build the solution, too. But when I try to open the project on UE 4.12, it gives me “The following module is missing…” error. When I try to rebuild, it gives an error and UE closes. After this step, VS2013 cannot build the project anymore, too. It gives the error below, too. As you can see, I’m new to UE4 and game programming generally. So what should I do? Note: Windows Development Kit 8.1 is installed. Thanks.

Creating library H:\UnrealProjects\RYO\Intermediate\Build\Win64\UE4Editor\Development\UE4Editor-RYO.lib and object H:\UnrealProjects\RYO\Intermediate\Build\Win64\UE4Editor\Development\UE4Editor-RYO.exp

RYO.cpp.obj : error LNK2019: unresolved external symbol “__declspec(dllimport) public: static class TBaseDelegate & __cdecl FCoreDelegates::GetObjectArrayForDebugVisualizersDelegate(void)” (_imp?GetObjectArrayForDebugVisualizersDelegate@FCoreDelegates@@SAAEAV?$TBaseDelegate@PEAVFFixedUObjectArray@■■■$V@@anonymous_user_9674a66c) referenced in function “void __cdecl `dynamic initializer for ‘GObjectArrayForDebugVisualizers’’(void)” (??__EGObjectArrayForDebugVisualizers@@YAXXZ)

RYOGameMode.cpp.obj : error LNK2001: unresolved external symbol “public: virtual bool __cdecl AGameMode::SetPause(class APlayerController *,class TBaseDelegate)” (?SetPause@AGameMode@@UEAA_NPEAVAPlayerController@@anonymous_user_e71e0d8a1?$TBaseDelegate@_N$$$V@@@Z)

RYO.generated.cpp.obj : error LNK2001: unresolved external symbol “public: virtual bool __cdecl AGameMode::SetPause(class APlayerController *,class TBaseDelegate)” (?SetPause@AGameMode@@UEAA_NPEAVAPlayerController@@anonymous_user_e71e0d8a1?$TBaseDelegate@_N$$$V@@@Z)

H:\UnrealProjects\RYO\Binaries\Win64\UE4Editor-RYO.dll : fatal error LNK1120: 2 unresolved externals

UBT error : Failed to produce item: H:\UnrealProjects\RYO\Binaries\Win64\UE4Editor-RYO.dll