Error building Player: Extracting referenced dlls failed.

In all of my projects i am now getting the "Error building Player: Extracting referenced dlls failed." error when trying to build. Even if i create a new empty project and build it straight away.

Anyone know how to resolve this? i tried reinstalling unity but it had no impact.

i am using 5.3.0f4 personal.

Error text is:

ArgumentException: The Assembly UnityEditor is referenced by UnityEditor.iOS.Extensions.Common ('/Applications/Unity/PlaybackEngines/iOSSupport/UnityEditor.iOS.Extensions.Common.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:156) UnityEditor.AssemblyHelper.FindAssembliesReferencedBy (System.String[] paths, System.String[] foldersToSearch, BuildTarget target) (at /Users/builduser/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:194) UnityEditor.HostView:OnGUI()

Thanks!