diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 0d67069b2..b4c059c73 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -684,7 +684,7 @@
 		4BB73ECF1B587A6700552FC2 /* Clock Signal.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.xml; path = "Clock Signal.entitlements"; sourceTree = "<group>"; };
 		4BBB142F1CD2CECE00BDB55C /* IntermediateShader.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = IntermediateShader.cpp; sourceTree = "<group>"; };
 		4BBB14301CD2CECE00BDB55C /* IntermediateShader.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = IntermediateShader.hpp; sourceTree = "<group>"; };
-		4BBC34241D2208B100FFC9DF /* CSCommonOptions.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CSCommonOptions.h; sourceTree = "<group>"; };
+		4BBC34241D2208B100FFC9DF /* CSFastLoading.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CSFastLoading.h; sourceTree = "<group>"; };
 		4BBF99081C8FBA6F0075DAFB /* CRTInputBufferBuilder.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = CRTInputBufferBuilder.cpp; sourceTree = "<group>"; };
 		4BBF99091C8FBA6F0075DAFB /* CRTInputBufferBuilder.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CRTInputBufferBuilder.hpp; sourceTree = "<group>"; };
 		4BBF990A1C8FBA6F0075DAFB /* CRTOpenGL.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = CRTOpenGL.cpp; sourceTree = "<group>"; };
@@ -806,7 +806,7 @@
 		4B2A53921D117D36003C6002 /* Machine */ = {
 			isa = PBXGroup;
 			children = (
-				4BBC34241D2208B100FFC9DF /* CSCommonOptions.h */,
+				4BBC34241D2208B100FFC9DF /* CSFastLoading.h */,
 				4B2A53931D117D36003C6002 /* CSKeyboardMachine.h */,
 				4B2A53941D117D36003C6002 /* CSMachine+Subclassing.h */,
 				4B2A53951D117D36003C6002 /* CSMachine.h */,
diff --git a/OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h b/OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h
index 20dce5f51..09487f836 100644
--- a/OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h	
+++ b/OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h	
@@ -4,7 +4,7 @@
 
 #import "CSMachine.h"
 #import "CSKeyboardMachine.h"
-#import "CSCommonOptions.h"
+#import "CSFastLoading.h"
 
 #import "CSAtari2600.h"
 #import "CSElectron.h"
diff --git a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift
index 2098b9f62..82c9f2499 100644
--- a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
+++ b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
@@ -184,9 +184,9 @@ class MachineDocument:
 
 	@IBOutlet var fastLoadingButton: NSButton!
 	@IBAction func setFastLoading(sender: NSButton!) {
-		if let commonOptionsMachine = machine as? CSCommonOptions {
+		if let fastLoadingMachine = machine as? CSFastLoading {
 			let useFastLoadingHack = sender.state == NSOnState
-			commonOptionsMachine.useFastLoadingHack = useFastLoadingHack
+			fastLoadingMachine.useFastLoadingHack = useFastLoadingHack
 			NSUserDefaults.standardUserDefaults().setBool(useFastLoadingHack, forKey: fastLoadingUserDefaultsKey)
 		}
 	}
@@ -197,9 +197,9 @@ class MachineDocument:
 			fastLoadingUserDefaultsKey: true
 		])
 
-		if let commonOptionsMachine = machine as? CSCommonOptions {
+		if let fastLoadingMachine = machine as? CSFastLoading {
 			let useFastLoadingHack = standardUserDefaults.boolForKey(self.fastLoadingUserDefaultsKey)
-			commonOptionsMachine.useFastLoadingHack = useFastLoadingHack
+			fastLoadingMachine.useFastLoadingHack = useFastLoadingHack
 			self.fastLoadingButton.state = useFastLoadingHack ? NSOnState : NSOffState
 		}
 	}
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSFastLoading.h b/OSBindings/Mac/Clock Signal/Machine/CSFastLoading.h
new file mode 100644
index 000000000..3c41389a0
--- /dev/null
+++ b/OSBindings/Mac/Clock Signal/Machine/CSFastLoading.h	
@@ -0,0 +1,11 @@
+//
+//  CSFastLoading.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 05/06/2016.
+//  Copyright © 2016 Thomas Harte. All rights reserved.
+//
+
+@protocol CSFastLoading <NSObject>
+@property (nonatomic, assign) BOOL useFastLoadingHack;
+@end
diff --git a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSElectron.h b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSElectron.h
index 0d911dccb..4d23a3536 100644
--- a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSElectron.h	
+++ b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSElectron.h	
@@ -8,9 +8,9 @@
 
 #import "CSMachine.h"
 #import "CSKeyboardMachine.h"
-#import "CSCommonOptions.h"
+#import "CSFastLoading.h"
 
-@interface CSElectron : CSMachine <CSKeyboardMachine, CSCommonOptions>
+@interface CSElectron : CSMachine <CSKeyboardMachine, CSFastLoading>
 
 - (void)setOSROM:(nonnull NSData *)rom;
 - (void)setBASICROM:(nonnull NSData *)rom;
diff --git a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSVic20.h b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSVic20.h
index 9aa0a638a..ef04a1f78 100644
--- a/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSVic20.h	
+++ b/OSBindings/Mac/Clock Signal/Machine/Wrappers/CSVic20.h	
@@ -8,9 +8,9 @@
 
 #import "CSMachine.h"
 #import "CSKeyboardMachine.h"
-#import "CSCommonOptions.h"
+#import "CSFastLoading.h"
 
-@interface CSVic20 : CSMachine <CSKeyboardMachine, CSCommonOptions>
+@interface CSVic20 : CSMachine <CSKeyboardMachine, CSFastLoading>
 
 - (void)setKernelROM:(nonnull NSData *)rom;
 - (void)setBASICROM:(nonnull NSData *)rom;