Build error for android Gear Vr Assembly-CSharp.dll could not be found on OSX

I am new to unity and c# so I have limited experience in dealing with issues like these. I had a working project until I followed this tutorial to add a teleportation system for my gear vr app https://www.youtube.com/watch?v=qjW4_1of7u4.

The teleportation code works in preview mode, when I try to run a build I get the following:

 ArgumentException: The Assembly UnityEditor is referenced by Assembly-CSharp ('Library/ScriptAssemblies/Assembly-CSharp.dll'). But the dll is not allowed to be included or could not be found.
 UnityEditor.AssemblyHelper.AddReferencedAssembliesRecurse (System.String assemblyPath, System.Collections.Generic.List`1 alreadyFoundAssemblies, System.String[] allAssemblyPaths, System.String[] foldersToSearch, System.Collections.Generic.Dictionary`2 cache, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:142)
 UnityEditor.AssemblyHelper.FindAssembliesReferencedBy (System.String[] paths, System.String[] foldersToSearch, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:179)
 UnityEditor.HostView:OnGUI()  

I have tried deleting the assembly files, Library and temp directories and ran the build again but the issue remains.

My Build settings are below:

Current unity version is 5.6.1f1 personal 64bit