diff --git a/Ample/Base.lproj/Preferences.xib b/Ample/Base.lproj/Preferences.xib
index d77c51c..06d60fc 100644
--- a/Ample/Base.lproj/Preferences.xib
+++ b/Ample/Base.lproj/Preferences.xib
@@ -33,6 +33,7 @@
                         </textFieldCell>
                         <connections>
                             <action selector="pathChanged:" target="-2" id="RRj-dC-q2y"/>
+                            <binding destination="yvB-HG-64y" name="enabled" keyPath="values.UseCustomMame" id="iex-A9-Db6"/>
                             <binding destination="yvB-HG-64y" name="value" keyPath="values.MamePath" id="H3O-1l-peo"/>
                         </connections>
                     </textField>
@@ -57,14 +58,14 @@
                         </connections>
                     </button>
                     <button verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="j7D-jC-17Q">
-                        <rect key="frame" x="96" y="208" width="137" height="18"/>
+                        <rect key="frame" x="96" y="208" width="139" height="18"/>
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMinY="YES"/>
-                        <buttonCell key="cell" type="check" title="Use System MAME" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="V61-mz-QFo">
+                        <buttonCell key="cell" type="check" title="Use Custom MAME" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="V61-mz-QFo">
                             <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                             <font key="font" metaFont="system"/>
                         </buttonCell>
                         <connections>
-                            <binding destination="yvB-HG-64y" name="value" keyPath="values.UseSystemMame" id="jIh-qD-e5H"/>
+                            <binding destination="yvB-HG-64y" name="value" keyPath="values.UseCustomMame" id="lH4-dm-kQC"/>
                         </connections>
                     </button>
                 </subviews>
diff --git a/Ample/Defaults.plist b/Ample/Defaults.plist
index 340dd9d..472d948 100644
--- a/Ample/Defaults.plist
+++ b/Ample/Defaults.plist
@@ -2,8 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
-	<key>UseSystemMame</key>
-	<true/>
+	<key>UseCustomMame</key>
+	<false/>
 	<key>AutoCloseLogWindow</key>
 	<true/>
 	<key>MamePath</key>
diff --git a/Ample/LaunchWindowController.m b/Ample/LaunchWindowController.m
index 93a8f3c..9cf73fc 100644
--- a/Ample/LaunchWindowController.m
+++ b/Ample/LaunchWindowController.m
@@ -91,6 +91,39 @@ static NSString *kContextMachine = @"kContextMachine";
     }
 }
 
+
+static NSURL *MameURL(void) {
+
+    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
+    NSBundle *bundle = [NSBundle mainBundle];
+        
+    if ([defaults boolForKey: @"UseSystemMame"]) {
+        NSString *path = [defaults stringForKey: @"MamePath"];
+        if (![path length]) return [NSURL fileURLWithPath: path];
+    }
+    
+    return [bundle URLForAuxiliaryExecutable: @"mame64"];
+
+    return nil;
+}
+
+static NSString *MamePath(void) {
+
+    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
+    NSBundle *bundle = [NSBundle mainBundle];
+
+    NSString *path;
+    
+    if ([defaults boolForKey: @"UseCustomMame"]) {
+        path = [defaults stringForKey: @"MamePath"];
+        if ([path length]) return path;
+    }
+    path = [bundle pathForAuxiliaryExecutable: @"mame64"];
+    if ([path length]) return path;
+    return nil;
+}
+
+
 static NSString * JoinArguments(NSArray *argv) {
 
     static NSCharacterSet *safe = nil;
@@ -110,7 +143,10 @@ static NSString * JoinArguments(NSArray *argv) {
 
     
     //unsigned ix = 0;
-    [rv appendString: @"mame"];
+    //[rv appendString: @"mame"];
+    NSString *path = MamePath();
+    path = path ? [path lastPathComponent] : @"mame";
+    [rv appendString: path];
     for (NSString *s in argv) {
         [rv appendString: @" "];
         NSUInteger l = [s length];
@@ -224,17 +260,20 @@ static NSString * JoinArguments(NSArray *argv) {
 
 
 
+
 - (IBAction)launchAction:(id)sender {
 
     if (![_args count]) return;
+        
+    NSURL *url = MameURL();
     
-    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
-    
-    
-    NSString *path = [defaults stringForKey: @"MamePath"];
-    if (![path length]) path = @"/usr/local/bin/mame";
-    
-    NSURL *url = [NSURL fileURLWithPath: path];
+    if (!url) {
+        NSAlert *alert = [NSAlert new];
+
+        [alert setMessageText: @"Unable to find MAME executable path"];
+        [alert runModal];
+        return;
+    }
     
     NSTask *task = [NSTask new];
     [task setExecutableURL: url];