Unreal Engine Fails to Launch/Build Executable

[anonymous_user_8da14b581 (anonymous_user_8da14b58)]

Hello,
I have a problem with my application. I am able to build/compile and rebuild the entire project. I am also able to launch the game outside of unreal with no issues. But when I click to launch it within the Unreal engine I get multiple issues when it’s building the executable. I appear to have multiple LNK errors, specifically it’s LNK 2001 and LNK2019. To try and fix it I have rebuilt it, merged it with an older working version (caused it to not work again), ran debugger to find missing dll files which there were a couple that got fixed. Thank you for any help or insight! The log is below -

LogPlayLevel: Using ‘git status’ to determine working set for adaptive non-unity build.
LogPlayLevel: Using Visual Studio 2017 14.15.26726 toolchain (C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726) and Windows 10.0.17134.0 SDK (C:\Program Files (x86)\Windows Kits\10).
LogPlayLevel: Building 1 action with 8 processes…
LogPlayLevel: [1/1] BuildingEscape.exe
LogPlayLevel: Creating library C:\Users\Documents\repos\BuildingEscape_01\BuildingEscape\Binaries\Win64\BuildingEscape.lib and object C:\Users\Documents\repos\BuildingEscape_01\BuildingEscape\Binaries\Win64\BuildingEscape.exp
LogPlayLevel: Module.Launch.cpp.obj : error LNK2019: unresolved external symbol “bool GIsGameAgnosticExe” (?GIsGameAgnosticExe@@3_NA) referenced in function “void __cdecl LaunchFixGameNameCase(void)” (?LaunchFixGameNameCase@@YAXXZ)
LogPlayLevel: Module.Core.5_of_10.cpp.obj : error LNK2001: unresolved external symbol “bool GIsGameAgnosticExe” (?GIsGameAgnosticExe@@3_NA)
LogPlayLevel: Module.BuildPatchServices.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.PakFile.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.NetworkFile.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.AutomationWorker.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.AutomationController.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Engine.16_of_40.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Engine.19_of_40.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Engine.24_of_40.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Engine.37_of_40.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.SandboxFile.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.ShaderCore.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.D3D11RHI.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.HTTP.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.7_of_10.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.9_of_10.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.ApplicationCore.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.CoreUObject.1_of_6.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Launch.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.2_of_10.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.5_of_10.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.6_of_10.cpp.obj : error LNK2001: unresolved external symbol “wchar_t * GInternalProjectName” (?GInternalProjectName@@3PA_WA)
LogPlayLevel: Module.Core.2_of_10.cpp.obj : error LNK2019: unresolved external symbol “wchar_t const * const GForeignEngineDir” (?GForeignEngineDir@@3PEB_WEB) referenced in function “public: static wchar_t const * __cdecl FGenericPlatformMisc::EngineDir(void)” (?EngineDir@FGenericPlatformMisc@@SAPEB_WXZ)
LogPlayLevel: Module.Core.5_of_10.cpp.obj : error LNK2019: unresolved external symbol “bool const GIsDebugGame” (?GIsDebugGame@@3_NB) referenced in function “public: static enum EBuildConfigurations::Type __cdecl FApp::GetBuildConfiguration(void)” (?GetBuildConfiguration@FApp@@SA?AW4Type@EBuildConfigurations@@XZ)
LogPlayLevel: C:\Users\Documents\repos\BuildingEscape_01\BuildingEscape\Binaries\Win64\BuildingEscape.exe : fatal error LNK1120: 4 unresolved externals
LogPlayLevel: ERROR: UBT ERROR: Failed to produce item: C:\Users\Documents\repos\BuildingEscape_01\BuildingEscape\Binaries\Win64\BuildingEscape.exe
LogPlayLevel: (see C:\Users\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.20\UBT-BuildingEscape-Win64-Development_2.txt for full exception trace)
LogPlayLevel: Total build time: 12.97 seconds (Parallel executor: 0.00 seconds)
LogPlayLevel: Took 13.2825841s to run UnrealBuildTool.exe, ExitCode=5
LogPlayLevel: ERROR: UnrealBuildTool failed. See log for more details. (C:\Users\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.20\UBT-BuildingEscape-Win64-Development_2.txt)
LogPlayLevel: (see C:\Users\AppData\Roaming\Unreal Engine\AutomationTool\Logs\C+Program+Files+Epic+Games+UE_4.20\Log.txt for full exception trace)
LogPlayLevel: AutomationTool exiting with ExitCode=5 (5)
LogPlayLevel: Completed Launch On Stage: Build Task, Time: 44.413977
LogPlayLevel: BUILD FAILED
PackagingResults: Error: Launch failed! Unknown Error

[Gulith421 (Gulith42)]

Did you find the problem?
I have the same issue, the engine doesn’t seem to find the “Core” module, altough it’s there in the .cs …

[Linxmas]

Cooking error : cannot link the “Core” module - Development / Programming & Scripting - Epic Developer Community Forums (unrealengine.com)
I have same issue. How did you fix it?

[Linxmas]

Also eventually figured it out myself.
Just deleted Source folder in project, just had empty c++ class created (that was the packaging issue) and all the safe to delete folders from this list:

Folders safe to delete to recompile everything

I want to recompile everything from the project (classes, shaders…) as the project had many changes. When I’m building the project for shipping form I even get a warning saying that a file is old or something like that and I should delete it. And to do that I want to delete every file that is created either by building the project or when it is cooked. So which of the following folders can be deleted so they are recreated by UE (some I know can be deleted and recreated by using Generate Visual S…

[Bino]

I recently got similar errors on a 5.4 C++ project out of no where. I had no code changes that could explain the issue. Cleaning the solution and rebuilding fixed it for me.