Unity WebGL Build fails in versions older than 2018.1.4

Question

I'm trying to build a WebGL Project in Unity, running on Windows 10. I've tried blank projects and I've tried several different versions. I'll be frank I haven't tried all of the versions older than 2018.1.4, but I've tried several 2018, 2019 and 2020 versions with no luck, 2018.1.4 is the last version I've been able to build WebGL on.

I've also tried some dozen fixes on various forums. Deleted the il2cpp_cache, deleted webGL_cache, moved the project to the root directory, I've been working at this for months. The errors are consistent across versions, whether it's a brand new project, or an updated version of a project that builds succesfully on 2018.1.4. stacks below.

Error 1

Failed running D:\Unity\2018.4.16f1\Editor\Data\il2cpp/build/il2cpp.exe --convert-to-cpp --dotnetprofile="legacyunity" --compile-cpp --libil2cpp-static --platform="WebGL" --architecture="EmscriptenJavaScript" --configuration="Release" --outputpath="D:\Unity_projects\DungeonAtTheEnd\Assets /../Temp/StagingArea/Data\Native\build.bc" --cachedirectory="D:\Unity_projects\DungeonAtTheEnd\Assets\..\Library/il2cpp_cache" --compiler-flags="-Oz -DIL2CPP_EXCEPTION_DISABLED=1 " --emit-method-map --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_AccessibilityModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_AIModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_AnimationModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ARModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_AssetBundleModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_AudioModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_BaselibModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ClothModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_CoreModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_CrashReportingModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_DirectorModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_FileSystemHttpModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_GameCenterModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_GridModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_HotReloadModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ImageConversionModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_IMGUIModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_InputModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_JSONSerializeModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_LocalizationModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ParticleSystemModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_PerformanceReportingModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_Physics2DModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_PhysicsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ProfilerModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_ScreenCaptureModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_SharedInternalsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_SpatialTrackingModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_SpriteMaskModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_SpriteShapeModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_StreamingModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_StyleSheetsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_SubstanceModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TerrainModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TerrainPhysicsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TextCoreModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TextRenderingModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TilemapModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TimelineModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_TLSModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UIElementsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UIModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UmbraModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UNETModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityAnalyticsModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityConnectModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityTestProtocolModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityWebRequestAssetBundleModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityWebRequestAudioModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityWebRequestModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityWebRequestTextureModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_UnityWebRequestWWWModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_VehiclesModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_VFXModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_VideoModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_VRModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_WebGLModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_WindModule_Dynamic.bc" --additional-libraries="D:\Unity\2018.4.16f1\Editor\Data\PlaybackEngines\WebGLSupport\BuildTools\lib\modules\WebGLSupport_XRModule_Dynamic.bc" --map-file-parser="D:\Unity\2018.4.16f1\Editor\Data\Tools\MapFileParser\MapFileParser.exe" --directory="D:\Unity_projects\DungeonAtTheEnd\Temp\StagingArea\Data\Managed" --generatedcppdir="D:\Unity_projects\DungeonAtTheEnd\Temp\StagingArea\Data\il2cppOutput" 

stdout:
Building build.bc with EmscriptenToolChain
    Output directory: D:\Unity_projects\DungeonAtTheEnd\Temp\StagingArea\Data\Native
    Cache directory: D:\Unity_projects\DungeonAtTheEnd\Library\il2cpp_cache
il2cpp.exe didn't catch exception: System.AggregateException: One or more errors occurred. ---> System.ComponentModel.Win32Exception: The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)
   --- End of inner exception stack trace ---
   at Unity.IL2CPP.Building.ParallelFor.RunWithResult[D,T](D[] data, Func`2 action)
   at Unity.IL2CPP.Building.CppProgramBuilder.BuildAllCppFiles(IEnumerable`1 sourceFilesToCompile, IBuildStatisticsCollector statisticsCollector)
   at Unity.IL2CPP.Building.CppProgramBuilder.Build(IBuildStatistics& statistics)
   at il2cpp.Program.DoRun(String[] args)
   at il2cpp.Program.Run(String[] args)
   at il2cpp.Program.Main(String[] args)
---> (Inner Exception #0) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #1) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #2) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #3) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #4) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #5) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #6) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #7) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #8) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #9) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(IntermediateObjectFileCompilationData data)
   at Unity.IL2CPP.Building.ParallelFor.<>c__DisplayClass1_0`2.<RunWithResult>b__0(Object o)<---

---> (Inner Exception #10) System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
   at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
   at Unity.IL2CPP.Shell.Execute(ExecuteArgs executeArgs, IExecuteController controller)
   at Unity.IL2CPP.Building.CppProgramBuilder.ProvideObjectFile(Interme<message truncated>

Error 2

Exception: D:\Unity\2018.4.16f1\Editor\Data\il2cpp/build/il2cpp.exe did not run properly!
UnityEditorInternal.Runner.RunProgram (UnityEditor.Utils.Program p, System.String exe, System.String args, System.String workingDirectory, UnityEditor.Scripting.Compilers.CompilerOutputParserBase parser) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:130)
UnityEditorInternal.Runner.RunManagedProgram (System.String exe, System.String args, System.String workingDirectory, UnityEditor.Scripting.Compilers.CompilerOutputParserBase parser, System.Action`1 setupStartInfo) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/BuildUtils.cs:73)
UnityEditorInternal.IL2CPPBuilder.RunIl2CppWithArguments (System.Collections.Generic.List`1 arguments, System.Action`1 setupStartInfo, System.String workingDirectory) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:376)
UnityEditorInternal.IL2CPPBuilder.ConvertPlayerDlltoCpp (System.String inputDirectory, System.String outputDirectory, System.String workingDirectory, Boolean platformSupportsManagedDebugging) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:357)
UnityEditorInternal.IL2CPPBuilder.Run () (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:211)
UnityEditorInternal.IL2CPPUtils.RunIl2Cpp (System.String stagingAreaData, IIl2CppPlatformProvider platformProvider, System.Action`1 modifyOutputBeforeCompile, UnityEditor.RuntimeClassRegistry runtimeClassRegistry) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/Il2Cpp/IL2CPPUtils.cs:42)
UnityEditor.WebGL.WebGlBuildPostprocessor.CompileBuild (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:374)
UnityEditor.WebGL.WebGlBuildPostprocessor.PostProcess (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:953)
UnityEditor.Modules.DefaultBuildPostprocessor.PostProcess (BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultBuildPostprocessor.cs:27)
UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTargetGroup targetGroup, BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at C:/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:288)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr) (at C:/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:179)

Error 3

Build completed with a result of 'Failed'
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr) (at C:/buildslave/unity/build/Modules/IMGUI/GUIUtility.cs:179)

Answer 1

Check if the folder path for the unity installation, project folder, or build location have any non-latin characters. If they do, then this may be the cause of your errors.