Unity 5.5 - WebGL - Build fail: Access to Plugins\Android\MainLibProj is denied

Hi

Today I got this weird error during WebGL build, it seems related to Facebook plugin? Any ideas how to resolve it?

il2cpp.exe didn't catch exception: System.UnauthorizedAccessException: Access to the path '<Path to my project>\Assets\Plugins\Android\MainLibProj' is denied.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)
   at Unity.IL2CPP.Building.Hashing.HashTools.HashOfFile(NPath path)
   at Unity.IL2CPP.Building.CppProgramBuilder.HashLinkerInvocation(LinkerInvocation linkerInvocation, IEnumerable`1 objectFiles)
   at Unity.IL2CPP.Building.CppProgramBuilder.PostprocessObjectFiles(IEnumerable`1 objectFiles, CppToolChainContext toolChainContext)
   at Unity.IL2CPP.Building.CppProgramBuilder.Build()
   at il2cpp.Program.DoRun(String[] args)
   at il2cpp.Program.Run(String[] args)
   at il2cpp.Program.Main(String[] args)

Try to exclude this folder from WebGL build via Plugin Inspector

The problem was solved.

WebGL build was clearly accessing at compile time plugin “Google Play Center” - which shouldn’t at all.

Wrapping platform dependant code helped to resolve the problem