Visual Studio bulid errors after using GenerateProjectFiles.bat

Development Pipeline & Plugins
, , , ,
1

After generating a project .sln file using GenerateProjectFiles.bat compilation of several engine modules fails in VisualStudio with the of the following error:

EXEC : error : UnrealBuildTool Exception: A conflicting instance of UnrealBuildTool is already running at this location: C:\\unreal\UnrealEngine\Engine\Binaries\DotNET\UnrealBuildTool.exe. A process manager may be used to determine the conflicting process and what tool may have launched it.

This appears to affect the following modules:
TestPAL, UnrealFileServer, UnrealLightMass, UnrealCEFSubProcess, UnrealPak, BootstrapPackagedGame, UnrealHeaderTool, BuildPatchTool, CrashReportClient, SlateViewer, SymbolDebugger, UnrealVersionSelector, UnrealWatchdog, UnrealFrontend, BlankProgram, ShaderCacheTool, UnrealVersionSelector, MiniDumpDiagnostics,

A .sln generated by creating a new C++ project from the UE4Editor UI does not appear to have this issue. Likewise I am able to build the project itself either by building it exclusively in Visual Studio, building manually using Build.bat or by omitting the ‘-Engine’ flag from the GenerateProjectFiles.bat command

Command used to generate project project files:

[Path-To-Engine]/Build/BatchFiles/GenerateProjectFiles.bat [Path-To-Project]/MyProject.uproject -Game -Engine -2015

This seems to have started occurring since upgrading to 4.18.3. I am using the same process to generate project files that I have for previous versions of the engine/project. Please let me know if I am doing something wrong here.

Thank You

2

Hi Clayton! Did you figure out what was happening?

3

This issue is triggered by running multiple build processes. Visual Studio 2017 number of build threads can be set from:
Tools → Options → Projects and Solutions → Build and Run → maximum number of parallel project builds

Setting it to 1 allowed my solution to build correctly. I would suggest setting the number of build processes back to default (8 in my case) after building the engine since it could have significant impact on Visual Studio performance.

4

Worked for me! (same trouble with UE 4.18 from git) It’s kind of a bummer since I’m seating on a 12 core CPU… The good news is although projects won’t run in parallel the .obj are still processed simultaneously, I’m using 100% cores except on linking phase.