WebGL build errors related to WebAsembly? Emscripten? I don't know...

Hi. Sorry if it is a wrong forum for this but I don't know where should I put it.
I get this error when trying to build for webgl platform. It happens only with the Web Assembly. It builds with asm.js (but it is deprecated so I don't want to use it).

Code (CSharp):

1.  
2. FileNotFoundException: C:\Projects\TheBlackMaze\Temp\StagingArea\Data\linkresult_wasm\build.wasm does not exist
3. System.IO.File.Copy (System.String sourceFileName, System.String destFileName, Boolean overwrite) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.IO/File.cs:107)
4. System.IO.File.Copy (System.String sourceFileName, System.String destFileName) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.IO/File.cs:86)
5. UnityEditor.WebGL.WebGlBuildPostprocessor.AssembleOutput (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:666)
6. UnityEditor.WebGL.WebGlBuildPostprocessor.PostProcess (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:957)
7. UnityEditor.Modules.DefaultBuildPostprocessor.PostProcess (BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultBuildPostprocessor.cs:27)
8. 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:286)
9. UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)
10.  

Of course I tried I to restart the unity, pc, reinstall, update, reimport, clearing cashe, running as administrator... the usual stuff. Before updating unity to 2018.3.10f1 there was a different error:

Code (csharp):

1.  
2. FileNotFoundException: C:\Projects\TheBlackMaze\Temp\StagingArea\Data\linkresult_wasm\build.temp.asm.js does not exist
3. System.IO.File.Copy (System.String sourceFileName, System.String destFileName, Boolean overwrite) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.IO/File.cs:107)
4. UnityEditor.FileUtil.UnityFileCopy (System.String from, System.String to, Boolean overwrite) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:210)
5. UnityEditor.FileUtil.CopyDirectoryFiltered (System.String source, System.String target, Boolean overwrite, System.Func`2 includeCallback, Boolean recursive) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:145)
6. UnityEditor.FileUtil.CopyDirectoryFiltered (System.String source, System.String target, Boolean overwrite, System.String regExExcludeFilter, Boolean recursive) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:121)
7. UnityEditor.FileUtil.CopyDirectoryRecursiveFiltered (System.String source, System.String target, Boolean overwrite, System.String regExExcludeFilter) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:102)
8. UnityEditor.FileUtil.CopyDirectoryRecursive (System.String source, System.String target, Boolean overwrite, Boolean ignoreMeta) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:92)
9. UnityEditor.FileUtil.CopyDirectoryRecursive (System.String source, System.String target) (at C:/buildslave/unity/build/Editor/Mono/FileUtil.cs:72)
10. UnityEditor.WebGL.WebGlBuildPostprocessor.EmscriptenLink (BuildPostProcessArgs args, Boolean wasmBuild, System.String sourceFiles, System.String sourceFilesHash) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:442)
11. UnityEditor.WebGL.WebGlBuildPostprocessor.LinkBuild (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:482)
12. UnityEditor.WebGL.WebGlBuildPostprocessor.PostProcess (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:954)
13. UnityEditor.Modules.DefaultBuildPostprocessor.PostProcess (BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultBuildPostprocessor.cs:27)
14. UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTargetGroup targetGroup, BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, BuildOptions options, UnityEditor.RuntimeClassRegistry

Any suggestions why this happens? Thanks!

 

Over hours I managed to get many different errors, including one with over 15000 characters...
Managed to fix the issue by cloning the repo again, reimporting and restarting unity multiple times. It worked after third time.