Error building Player: Extracting referenced dlls failed.

Every time I try to build my project I keep getting these 2 errors

 NullReferenceException: Object reference not set to an instance of an object
 UnityEditor.Modules.DefaultPluginImporterExtension+<GetCompatiblePlugins>c__AnonStorey6F.<>m__F8 (UnityEditor.PluginImporter imp) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultPluginImporterExtension.cs:133)
 System.Linq.Enumerable+<CreateWhereIterator>c__Iterator1D`1[UnityEditor.PluginImporter].MoveNext ()
 System.Collections.Generic.List`1[UnityEditor.PluginImporter].AddEnumerable (IEnumerable`1 enumerable) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:128)
 System.Collections.Generic.List`1[UnityEditor.PluginImporter]..ctor (IEnumerable`1 collection) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:65)
 System.Linq.Enumerable.ToArray[PluginImporter] (IEnumerable`1 source)
 UnityEditor.Modules.DefaultPluginImporterExtension.GetCompatiblePlugins (System.String buildTargetName) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultPluginImporterExtension.cs:133)
 UnityEditor.Modules.DefaultPluginImporterExtension.CheckFileCollisions (System.String buildTargetName) (at C:/buildslave/unity/build/Editor/Mono/Modules/DefaultPluginImporterExtension.cs:157)
 UnityEditorInternal.PluginsHelper.CheckFileCollisions (BuildTarget buildTarget) (at C:/buildslave/unity/build/Editor/Mono/Plugins/PluginsHelper.cs:25)
 UnityEditor.HostView:OnGUI()

 NullReferenceException: Object reference not set to an instance of an object
 UnityEditor.PluginImporter+<GetImporters>c__AnonStoreyE.<>m__F (UnityEditor.PluginImporter imp) (at C:/buildslave/unity/build/artifacts/generated/common/editor/PluginImporterBindings.gen.cs:107)
 System.Linq.Enumerable+<CreateWhereIterator>c__Iterator1D`1[UnityEditor.PluginImporter].MoveNext ()
 System.Collections.Generic.List`1[UnityEditor.PluginImporter].AddEnumerable (IEnumerable`1 enumerable) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:128)
 System.Collections.Generic.List`1[UnityEditor.PluginImporter]..ctor (IEnumerable`1 collection) (at /Users/builduser/buildslave/mono-runtime-and-classlibs/build/mcs/class/corlib/System.Collections.Generic/List.cs:65)
 System.Linq.Enumerable.ToArray[PluginImporter] (IEnumerable`1 source)
 UnityEditor.PluginImporter.GetImporters (System.String platformName) (at C:/buildslave/unity/build/artifacts/generated/common/editor/PluginImporterBindings.gen.cs:106)
 UnityEditor.PluginImporter.GetImporters (BuildTarget platform) (at C:/buildslave/unity/build/artifacts/generated/common/editor/PluginImporterBindings.gen.cs:114)
 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 C:/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:123)
 UnityEditor.AssemblyHelper.FindAssembliesReferencedBy (System.String[] paths, System.String[] foldersToSearch, BuildTarget target) (at C:/buildslave/unity/build/Editor/Mono/AssemblyHelper.cs:192)
 UnityEditor.HostView:OnGUI()
 

I've tried reinstalling unity and changing .NET 2.0 subset to .NET 2.0 but nothing has changed. I do not have any plugins added.