diff --git a/OpenRA.Launcher.Mac/Controller.h b/OpenRA.Launcher.Mac/Controller.h
index 5840cb83a6..d16ba4bcff 100644
--- a/OpenRA.Launcher.Mac/Controller.h
+++ b/OpenRA.Launcher.Mac/Controller.h
@@ -16,10 +16,14 @@
 {
 	SidebarEntry *sidebarItems;
 	GameInstall *game;
+	NSDictionary *allMods;
 	IBOutlet NSOutlineView *outlineView;
 	IBOutlet WebView *webView;
 }
-- (void)launchGame;
+@property(readonly) NSDictionary *allMods;
+
+- (void)launchMod:(NSString *)mod;
+- (void)populateModInfo;
 - (SidebarEntry *)sidebarModsTree;
 - (SidebarEntry *)sidebarOtherTree;
 
diff --git a/OpenRA.Launcher.Mac/Controller.m b/OpenRA.Launcher.Mac/Controller.m
index 161de5409b..be31fcda18 100644
--- a/OpenRA.Launcher.Mac/Controller.m
+++ b/OpenRA.Launcher.Mac/Controller.m
@@ -14,6 +14,7 @@
 #import "JSBridge.h"
 
 @implementation Controller
+@synthesize allMods;
 
 - (void) awakeFromNib
 {
@@ -25,6 +26,7 @@
 	[col setDataCell:imageAndTextCell];
 	
 	sidebarItems = [[SidebarEntry headerWithTitle:@""] retain];
+	[self populateModInfo];
 	id modsRoot = [self sidebarModsTree];
 	[sidebarItems addChild:modsRoot];
 	id otherRoot = [self sidebarOtherTree];
@@ -45,21 +47,25 @@
 	[outlineView expandItem:otherRoot expandChildren:YES];
 }
 
-- (void) dealloc
+- (void)dealloc
 {
 	[sidebarItems release]; sidebarItems = nil;
 	[super dealloc];
 }
 
-- (SidebarEntry *)sidebarModsTree
+- (void)populateModInfo
 {
 	// Get info for all installed mods
-	id modnames = [game installedMods];
-	NSArray *allMods = [game infoForMods:modnames];
-	
+	[allMods autorelease];
+	allMods = [[game infoForMods:[game installedMods]] retain];	
+}
+
+- (SidebarEntry *)sidebarModsTree
+{
 	SidebarEntry *rootItem = [SidebarEntry headerWithTitle:@"MODS"];
-	for (id aMod in allMods)
+	for (id key in allMods)
 	{	
+		id aMod = [allMods objectForKey:key];
 		if ([aMod standalone])
 		{
 			id child = [SidebarEntry entryWithMod:aMod allMods:allMods baseURL:[[game gameURL] URLByAppendingPathComponent:@"mods"]];
@@ -79,9 +85,9 @@
 	return rootItem;
 }
 
-- (void)launchGame
+- (void)launchMod:(NSString *)mod
 {
-	[game launchGame];
+	[game launchMod:mod];
 }
 
 #pragma mark Sidebar Datasource and Delegate
@@ -156,4 +162,8 @@ objectValueForTableColumn:(NSTableColumn *)tableColumn
 	[windowObject setValue:[JSBridge sharedInstance] forKey:@"external"];
 }
 
+- (void)webView:(WebView *)webView addMessageToConsole:(NSDictionary *)dictionary
+{
+	NSLog(@"%@",dictionary);
+}
 @end
diff --git a/OpenRA.Launcher.Mac/GameInstall.h b/OpenRA.Launcher.Mac/GameInstall.h
index 52b0e6721a..be32a7d3b1 100644
--- a/OpenRA.Launcher.Mac/GameInstall.h
+++ b/OpenRA.Launcher.Mac/GameInstall.h
@@ -15,9 +15,9 @@
 @property(readonly) NSURL *gameURL;
 
 -(id)initWithURL:(NSURL *)path;
--(void)launchGame;
+-(void)launchMod:(NSString *)mod;
 - (NSString *)runUtilityQuery:(NSString *)arg;
 - (void)runUtilityQuery:(NSString *)arg handleOutput:(id)obj withMethod:(SEL)sel;
 - (NSArray *)installedMods;
-- (NSArray *)infoForMods:(NSArray *)mods;
+- (NSDictionary *)infoForMods:(NSArray *)mods;
 @end
diff --git a/OpenRA.Launcher.Mac/GameInstall.m b/OpenRA.Launcher.Mac/GameInstall.m
index 61d520bfb9..1a71013bcd 100644
--- a/OpenRA.Launcher.Mac/GameInstall.m
+++ b/OpenRA.Launcher.Mac/GameInstall.m
@@ -35,12 +35,12 @@
 	return [mods componentsSeparatedByString:@"\n"];
 }
 
-- (NSArray *)infoForMods:(NSArray *)mods
+- (NSDictionary *)infoForMods:(NSArray *)mods
 {
 	id query = [NSString stringWithFormat:@"-i=%@",[mods componentsJoinedByString:@","]];
 	NSArray *lines = [[self runUtilityQuery:query] componentsSeparatedByString:@"\n"];
 	
-	NSMutableArray *ret = [NSMutableArray array];
+	NSMutableDictionary *ret = [NSMutableDictionary dictionary];
 	NSMutableDictionary *fields = nil;
 	NSString *current = nil;
 	for (id l in lines)
@@ -68,7 +68,7 @@
 			if (current != nil)
 			{	
 				id url = [gameURL URLByAppendingPathComponent:[NSString stringWithFormat:@"mods/%@",current]];
-				[ret addObject:[Mod modWithId:current fields:fields baseURL:url]];
+				[ret setObject:[Mod modWithId:current fields:fields baseURL:url] forKey:current];
 			}
 			NSLog(@"Parsing mod %@",value);
 			current = value;
@@ -82,17 +82,17 @@
 	if (current != nil)
 	{	
 		id url = [gameURL URLByAppendingPathComponent:[NSString stringWithFormat:@"mods/%@",current]];
-		[ret addObject:[Mod modWithId:current fields:fields baseURL:url]];
+		[ret setObject:[Mod modWithId:current fields:fields baseURL:url] forKey:current];
 	}
 	
 	return ret;
 }
 
--(void)launchGame
+-(void)launchMod:(NSString *)mod
 {
 	// Use LaunchServices because neither NSTask or NSWorkspace support Info.plist _and_ arguments pre-10.6
 	NSString *path = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"OpenRA.app/Contents/MacOS/OpenRA"];
-	NSArray *args = [NSArray arrayWithObjects:[gameURL absoluteString], @"mono", @"--debug", @"OpenRA.Game.exe", @"Game.Mods=ra",nil];
+	NSArray *args = [NSArray arrayWithObjects:[gameURL absoluteString], @"mono", @"--debug", @"OpenRA.Game.exe", [NSString stringWithFormat:@"Game.Mods=%@",mod],nil];
 
 	FSRef appRef;
 	CFURLGetFSRef((CFURLRef)[NSURL URLWithString:path], &appRef);
diff --git a/OpenRA.Launcher.Mac/JSBridge.m b/OpenRA.Launcher.Mac/JSBridge.m
index 394119df5d..d1ae80e43c 100644
--- a/OpenRA.Launcher.Mac/JSBridge.m
+++ b/OpenRA.Launcher.Mac/JSBridge.m
@@ -38,7 +38,7 @@ static JSBridge *SharedInstance;
 	if (self != nil)
 	{
 		methods = [[NSDictionary dictionaryWithObjectsAndKeys:
-						@"launchCurrentMod", NSStringFromSelector(@selector(launchCurrentMod)),
+						@"launchMod", NSStringFromSelector(@selector(launchMod:)),
 						@"log", NSStringFromSelector(@selector(log:)),
 						@"fileExistsInMod", NSStringFromSelector(@selector(fileExists:inMod:)),
 					nil] retain];
@@ -59,10 +59,17 @@ static JSBridge *SharedInstance;
 
 #pragma mark JS methods
 
-- (void)launchCurrentMod
+- (BOOL)launchMod:(NSString *)aMod
 {
-	NSLog(@"launchcurrent");
-	[controller launchGame];
+	id mod = [[controller allMods] objectForKey:aMod];
+	if (mod == nil)
+	{
+		NSLog(@"Invalid or unknown mod: %@", aMod);
+		return NO;
+	}
+	
+	[controller launchMod:aMod];
+	return YES;
 }
 
 - (void)log:(NSString *)message
@@ -72,8 +79,19 @@ static JSBridge *SharedInstance;
 
 - (BOOL)fileExists:(NSString *)aFile inMod:(NSString *)aMod
 {
-	NSLog(@"File %@ exists in mod %@",aFile, aMod);
-	return NO;
+	id mod = [[controller allMods] objectForKey:aMod];
+	if (mod == nil)
+	{
+		NSLog(@"Invalid or unknown mod: %@", aMod);
+		return NO;
+	}
+	
+	// Disallow traversing up the directory tree
+	id path = [[[mod baseURL] absoluteString]
+			   stringByAppendingPathComponent:[aFile stringByReplacingOccurrencesOfString:@"../"
+																			   withString:@""]];
+	
+	return [[NSFileManager defaultManager] fileExistsAtPath:path];
 }
 
 @end
diff --git a/OpenRA.Launcher.Mac/Mod.h b/OpenRA.Launcher.Mac/Mod.h
index b8ea2393db..58d34c503b 100644
--- a/OpenRA.Launcher.Mac/Mod.h
+++ b/OpenRA.Launcher.Mac/Mod.h
@@ -24,10 +24,9 @@
 @property (readonly) NSString *author;
 @property (readonly) NSString *description;
 @property (readonly) NSString *requires;
+@property (readonly) NSURL *baseURL;
 @property (readonly) BOOL standalone;
 
 + (id)modWithId:(NSString *)mid fields:(id)fields baseURL:(NSURL *)url;
 - (id)initWithId:(NSString *)anId fields:(NSDictionary *)fields baseURL:(NSURL *)url;
-
-- (NSURL *)pageURL;
 @end
diff --git a/OpenRA.Launcher.Mac/Mod.m b/OpenRA.Launcher.Mac/Mod.m
index 68ecff5770..f8d90941e7 100644
--- a/OpenRA.Launcher.Mac/Mod.m
+++ b/OpenRA.Launcher.Mac/Mod.m
@@ -17,6 +17,7 @@
 @synthesize description;
 @synthesize requires;
 @synthesize standalone;
+@synthesize baseURL;
 
 + (id)modWithId:(NSString *)mod fields:(id)fields baseURL:(NSURL *)url
 {
@@ -54,9 +55,4 @@
 	[super dealloc];
 }
 
-- (NSURL *)pageURL
-{
-	return [baseURL URLByAppendingPathComponent:@"mod.html"];
-}
-
 @end
diff --git a/OpenRA.Launcher.Mac/SidebarEntry.h b/OpenRA.Launcher.Mac/SidebarEntry.h
index ba83f1a6f9..02d0337a00 100644
--- a/OpenRA.Launcher.Mac/SidebarEntry.h
+++ b/OpenRA.Launcher.Mac/SidebarEntry.h
@@ -25,7 +25,7 @@
 
 + (id)headerWithTitle:(NSString *)aTitle;
 + (id)entryWithTitle:(NSString *)aTitle url:(NSURL *)aURL icon:(id)anIcon;
-+ (id)entryWithMod:(Mod *)baseMod allMods:(NSArray *)allMods baseURL:(NSURL *)aURL;
++ (id)entryWithMod:(Mod *)baseMod allMods:(NSDictionary *)allMods baseURL:(NSURL *)aURL;
 - (id)initWithTitle:(NSString *)aTitle url:(NSURL *)aURL icon:(id)anIcon isHeader:(BOOL)aHeader;
 - (void)addChild:(id)child;
 - (NSURL *)url;
diff --git a/OpenRA.Launcher.Mac/SidebarEntry.m b/OpenRA.Launcher.Mac/SidebarEntry.m
index 2310149576..ad2a088275 100644
--- a/OpenRA.Launcher.Mac/SidebarEntry.m
+++ b/OpenRA.Launcher.Mac/SidebarEntry.m
@@ -29,7 +29,7 @@
 	return newObject;
 }
 
-+ (id)entryWithMod:(Mod *)baseMod allMods:(NSArray *)allMods baseURL:(NSURL *)baseURL
++ (id)entryWithMod:(Mod *)baseMod allMods:(NSDictionary *)allMods baseURL:(NSURL *)baseURL
 {
 	// TODO: Get the mod icon from the Mod
 	// Temporary hack until mods define an icon
@@ -40,8 +40,9 @@
 	
 	id ret = [SidebarEntry entryWithTitle:[baseMod title] url:url icon:icon];
 	
-	for (id aMod in allMods)
+	for (id key in allMods)
 	{
+		id aMod = [allMods objectForKey:key];
 		if (![[aMod requires] isEqualToString:[baseMod mod]])
 			continue;
 		
diff --git a/mods/cnc/mod.html b/mods/cnc/mod.html
index f84065e5b1..7de0b9f6d0 100644
--- a/mods/cnc/mod.html
+++ b/mods/cnc/mod.html
@@ -14,6 +14,7 @@
             	padding: 20px 0px;
             	width:100%;
             	height:100%;
+            	overflow:hidden;
             }
 
             div#header
@@ -21,6 +22,7 @@
             	margin-top: 30px;
             	height: 66px;
             	text-align:center;
+            	overflow:hidden;
             }
 
             div.bar
@@ -40,16 +42,21 @@
             div#content
             {
             	text-align: justify;
-            	width:50%;
             	padding-left:50px;
+            	overflow:hidden;
             }
 
-            div#buttons
+            div.buttons
             {
             	position:absolute;
             	bottom:0px;
             	padding:20px;
             }
+            
+            div.desc
+            {
+                font-size:0.75em;
+            }
 
             .button
             {
@@ -57,7 +64,7 @@
             	border-radius: 10px;
             	margin:10px;
             	height:40px;
-            	width:150px;
+            	width:170px;
             	color:white;
             	font-weight:bold;
             	font-size:1em;
@@ -75,8 +82,42 @@
             }
 
         </style>
+        <script type="text/javascript">
+        // Check which packages are installed.
+        // Returns 1 if basic files are installed
+        // Returns 2 if basic files plus music are installed
+        function packagesInstalled()
+        {
+            if (window.external.fileExistsInMod('packages/conquer.mix','cnc') != 1)
+                return 0;
+            
+            return (window.external.fileExistsInMod('packages/scores.mix','cnc') == 1) ? 2 : 1;
+        }
+        
+        function play()
+        {
+            window.external.launchMod("cnc");
+        }
+        
+        function installFromCD()
+        {
+            window.external.log("installFromCD()");
+        }
+        
+        function installFromWeb()
+        {
+            window.external.log("installFromWeb()");
+        }
+
+        function onLoad()
+        {
+            document.getElementById("buttons-install").style.display = (packagesInstalled() == 0) ? "" : "none";
+            document.getElementById("buttons-upgrade").style.display = (packagesInstalled() == 1) ? "" : "none";
+            document.getElementById("buttons-play").style.display = (packagesInstalled() == 2) ? "" : "none";
+        }
+        </script>
 	</head>
-	<body>
+	<body onload="onLoad();">
 		<div id="header" class="bar">
 			<h1>Command&nbsp;&amp;&nbsp;Conquer</h1>
 		</div>
@@ -93,9 +134,23 @@
 				    </ul>
 				</div>
 			</div>
-			<div id="buttons">
-			    <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
-			    <input type="button" class="button" onclick="window.external.fileExistsInMod('foo.mix','ra');"value="Debug" />
+			<div id="buttons-install" class="buttons">
+			    <div class="desc">The original game data is required before you can play this mod.<br />
+			        Installing from web will install the minimal files required to play.<br />
+			        Installing from CD will also install the music and movie files for an improved game experience.
+			    </div>
+			    <input type="button" class="button" onclick="installFromWeb();" value="Install from Web" />
+			    <input type="button" class="button" onclick="installFromCD();" value="Install from CD" />
+			</div>
+			<div id="buttons-upgrade" class="buttons" style="display:none">
+			    <div class="desc">
+			        Upgrade from CD to install the original music and movie files for an improved game experience.
+			    </div>
+			    <input type="button" class="button" onclick="play();" value="Play" />
+			    <input type="button" class="button" onclick="installFromCD();" value="Upgrade from CD" />
+			</div>
+			<div id="buttons-play" class="buttons" style="display:none">
+			    <input type="button" class="button" onclick="play();" value="Play" />
 			</div>
 		</div>
 	</body>
diff --git a/mods/d2k/mod.html b/mods/d2k/mod.html
index f838912df8..b165eb0d51 100644
--- a/mods/d2k/mod.html
+++ b/mods/d2k/mod.html
@@ -1,6 +1,6 @@
 <html>
 	<body>
         <h1>Dune 2000</h1>
-        <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
+        <input type="button" class="button" onclick="window.external.launchMod('d2k')" value="Play" />
 	</body>
 </html>
diff --git a/mods/default/mod.html b/mods/default/mod.html
index 143ce7d04e..33580f99be 100644
--- a/mods/default/mod.html
+++ b/mods/default/mod.html
@@ -1,6 +1,6 @@
 <html>
 	<body>
         <h1>Default Mod</h1>
-        <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
+        <input type="button" class="button" onclick="window.external.launchMod('default')" value="Play" />
 	</body>
 </html>
diff --git a/mods/example/mod.html b/mods/example/mod.html
index cd00c6bc33..b57a2f3614 100644
--- a/mods/example/mod.html
+++ b/mods/example/mod.html
@@ -2,6 +2,6 @@
 	<body>
         <h1>Example Mod</h1>
         <h2>Demonstrates how to add a new unit by adding a soviet supply truck.</h2>
-        <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
+        <input type="button" class="button" onclick="window.external.launchMod('example')" value="Play" />
 	</body>
 </html>
diff --git a/mods/ra/mod.html b/mods/ra/mod.html
index e44446f9a9..1b4994d62d 100644
--- a/mods/ra/mod.html
+++ b/mods/ra/mod.html
@@ -1,6 +1,6 @@
 <html>
 	<body>
         <h1>Red Alert</h1>
-        <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
+        <input type="button" class="button" onclick="window.external.launchMod('ra')" value="Play" />
 	</body>
 </html>
diff --git a/mods/ra_perf/mod.html b/mods/ra_perf/mod.html
index 0c95bf1dc9..a036413a4b 100644
--- a/mods/ra_perf/mod.html
+++ b/mods/ra_perf/mod.html
@@ -2,6 +2,6 @@
 	<body>
         <h1>RA Performance Tests</h1>
         <h2>Adds special performance test maps to ra.</h2>
-        <input type="button" class="button" onclick="window.external.launchCurrentMod();" value="Play" />
+        <input type="button" class="button" onclick="window.external.launchMod('ra_perf')" value="Play" />
 	</body>
 </html>