diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 060d6ef83..172f4654c 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -39,6 +39,7 @@
 		4B55CE591C3B7D360093A61B /* ElectronDocument.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B55CE571C3B7D360093A61B /* ElectronDocument.swift */; };
 		4B55CE5D1C3B7D6F0093A61B /* CSOpenGLView.m in Sources */ = {isa = PBXBuildFile; fileRef = 4B55CE5C1C3B7D6F0093A61B /* CSOpenGLView.m */; };
 		4B55CE5F1C3B7D960093A61B /* MachineDocument.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B55CE5E1C3B7D960093A61B /* MachineDocument.swift */; };
+		4B643F3F1D77B88000D431D6 /* DocumentController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B643F3E1D77B88000D431D6 /* DocumentController.swift */; };
 		4B69FB3D1C4D908A00B5F0AA /* Tape.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B69FB3B1C4D908A00B5F0AA /* Tape.cpp */; };
 		4B69FB441C4D941400B5F0AA /* TapeUEF.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B69FB421C4D941400B5F0AA /* TapeUEF.cpp */; };
 		4B69FB461C4D950F00B5F0AA /* libz.tbd in Frameworks */ = {isa = PBXBuildFile; fileRef = 4B69FB451C4D950F00B5F0AA /* libz.tbd */; };
@@ -425,6 +426,7 @@
 		4B55CE5B1C3B7D6F0093A61B /* CSOpenGLView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CSOpenGLView.h; sourceTree = "<group>"; };
 		4B55CE5C1C3B7D6F0093A61B /* CSOpenGLView.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = CSOpenGLView.m; sourceTree = "<group>"; };
 		4B55CE5E1C3B7D960093A61B /* MachineDocument.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = MachineDocument.swift; sourceTree = "<group>"; };
+		4B643F3E1D77B88000D431D6 /* DocumentController.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = DocumentController.swift; sourceTree = "<group>"; };
 		4B69FB3B1C4D908A00B5F0AA /* Tape.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Tape.cpp; sourceTree = "<group>"; };
 		4B69FB3C1C4D908A00B5F0AA /* Tape.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Tape.hpp; sourceTree = "<group>"; };
 		4B69FB421C4D941400B5F0AA /* TapeUEF.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = TapeUEF.cpp; sourceTree = "<group>"; };
@@ -976,6 +978,14 @@
 			path = Views;
 			sourceTree = "<group>";
 		};
+		4B643F3D1D77B88000D431D6 /* Document Controller */ = {
+			isa = PBXGroup;
+			children = (
+				4B643F3E1D77B88000D431D6 /* DocumentController.swift */,
+			);
+			path = "Document Controller";
+			sourceTree = "<group>";
+		};
 		4B69FB391C4D908A00B5F0AA /* Storage */ = {
 			isa = PBXGroup;
 			children = (
@@ -1365,6 +1375,7 @@
 		4BB73EA01B587A5100552FC2 /* Clock Signal */ = {
 			isa = PBXGroup;
 			children = (
+				4B643F3D1D77B88000D431D6 /* Document Controller */,
 				4BE5F85A1C3E1C2500C43F01 /* Resources */,
 				4BB73ECF1B587A6700552FC2 /* Clock Signal.entitlements */,
 				4B1414501B58848C00E04248 /* ClockSignal-Bridging-Header.h */,
@@ -1919,6 +1930,7 @@
 				4BB697CE1D4BA44400248BDF /* CommodoreGCR.cpp in Sources */,
 				4BBF99151C8FBA6F0075DAFB /* CRTOpenGL.cpp in Sources */,
 				4B0CCC451C62D0B3001CAC5F /* CRT.cpp in Sources */,
+				4B643F3F1D77B88000D431D6 /* DocumentController.swift in Sources */,
 				4BB697C71D4B558F00248BDF /* Factors.cpp in Sources */,
 				4B55CE591C3B7D360093A61B /* ElectronDocument.swift in Sources */,
 				4B4DC82B1D2C27A4003C5BF8 /* SerialBus.cpp in Sources */,
diff --git a/OSBindings/Mac/Clock Signal/Base.lproj/MainMenu.xib b/OSBindings/Mac/Clock Signal/Base.lproj/MainMenu.xib
index 012c3874d..5c4f1b32f 100644
--- a/OSBindings/Mac/Clock Signal/Base.lproj/MainMenu.xib	
+++ b/OSBindings/Mac/Clock Signal/Base.lproj/MainMenu.xib	
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="9532" systemVersion="15E65" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="9532" systemVersion="15G31" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="9532"/>
     </dependencies>
@@ -13,6 +13,7 @@
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
         <customObject id="Voe-Tx-rLC" customClass="AppDelegate" customModule="Clock_Signal" customModuleProvider="target"/>
         <customObject id="YLy-65-1bz" customClass="NSFontManager"/>
+        <customObject id="SOe-RA-8of" customClass="DocumentController" customModule="Clock_Signal" customModuleProvider="target"/>
         <menu title="Main Menu" systemMenu="main" id="AYu-sK-qS6">
             <items>
                 <menuItem title="Clock Signal" id="1Xt-HY-uBw">
diff --git a/OSBindings/Mac/Clock Signal/Document Controller/DocumentController.swift b/OSBindings/Mac/Clock Signal/Document Controller/DocumentController.swift
new file mode 100644
index 000000000..eedf4b3bd
--- /dev/null
+++ b/OSBindings/Mac/Clock Signal/Document Controller/DocumentController.swift	
@@ -0,0 +1,20 @@
+//
+//  DocumentController.swift
+//  Clock Signal
+//
+//  Created by Thomas Harte on 18/06/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+import Cocoa
+
+class DocumentController: NSDocumentController {
+	override func documentForURL(url: NSURL) -> NSDocument? {
+		return super.documentForURL(url)
+	}
+//	override func newDocument(sender: AnyObject?) {
+//		let window = NSWindow(contentViewController: NewDocumentViewController())
+//		window.title = "Choose a Machine"
+//		window.makeKeyAndOrderFront(self)
+//	}
+}