diff --git a/ui/cocoa.m b/ui/cocoa.m
index 00e3db69c9..420b2411c1 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -129,6 +129,9 @@ bool stretch_video;
 NSTextField *pauseLabel;
 NSArray * supportedImageFileTypes;
 
+static QemuSemaphore display_init_sem;
+static QemuSemaphore app_started_sem;
+
 // Utility functions to run specified code block with iothread lock held
 typedef void (^CodeBlock)(void);
 typedef bool (^BoolCodeBlock)(void);
@@ -325,6 +328,7 @@ static void handleAnyDeviceErrors(Error * err)
     NSWindow *fullScreenWindow;
     float cx,cy,cw,ch,cdx,cdy;
     CGDataProviderRef dataProviderRef;
+    pixman_image_t *pixman_image;
     BOOL modifiers_state[256];
     BOOL isMouseGrabbed;
     BOOL isFullscreen;
@@ -383,8 +387,10 @@ QemuCocoaView *cocoaView;
 {
     COCOA_DEBUG("QemuCocoaView: dealloc\n");
 
-    if (dataProviderRef)
+    if (dataProviderRef) {
         CGDataProviderRelease(dataProviderRef);
+        pixman_image_unref(pixman_image);
+    }
 
     [super dealloc];
 }
@@ -535,13 +541,16 @@ QemuCocoaView *cocoaView;
     }
 
     // update screenBuffer
-    if (dataProviderRef)
+    if (dataProviderRef) {
         CGDataProviderRelease(dataProviderRef);
+        pixman_image_unref(pixman_image);
+    }
 
     //sync host window color space with guests
     screen.bitsPerPixel = PIXMAN_FORMAT_BPP(image_format);
     screen.bitsPerComponent = DIV_ROUND_UP(screen.bitsPerPixel, 8) * 2;
 
+    pixman_image = image;
     dataProviderRef = CGDataProviderCreateWithData(NULL, pixman_image_get_data(image), w * 4 * h, NULL);
 
     // update windows
@@ -1013,7 +1022,6 @@ QemuCocoaView *cocoaView;
 #endif
 {
 }
-- (void)startEmulationWithArgc:(int)argc argv:(char**)argv;
 - (void)doToggleFullScreen:(id)sender;
 - (void)toggleFullScreen:(id)sender;
 - (void)showQEMUDoc:(id)sender;
@@ -1101,8 +1109,8 @@ QemuCocoaView *cocoaView;
 - (void)applicationDidFinishLaunching: (NSNotification *) note
 {
     COCOA_DEBUG("QemuCocoaAppController: applicationDidFinishLaunching\n");
-    // launch QEMU, with the global args
-    [self startEmulationWithArgc:gArgc argv:(char **)gArgv];
+    /* Tell cocoa_display_init to proceed */
+    qemu_sem_post(&app_started_sem);
 }
 
 - (void)applicationWillTerminate:(NSNotification *)aNotification
@@ -1145,15 +1153,6 @@ QemuCocoaView *cocoaView;
     [cocoaView raiseAllKeys];
 }
 
-- (void)startEmulationWithArgc:(int)argc argv:(char**)argv
-{
-    COCOA_DEBUG("QemuCocoaAppController: startEmulationWithArgc\n");
-
-    int status;
-    status = qemu_main(argc, argv, *_NSGetEnviron());
-    exit(status);
-}
-
 /* We abstract the method called by the Enter Fullscreen menu item
  * because Mac OS 10.7 and higher disables it. This is because of the
  * menu item's old selector's name toggleFullScreen:
@@ -1489,7 +1488,9 @@ QemuCocoaView *cocoaView;
 - (void)sendEvent:(NSEvent *)event
 {
     COCOA_DEBUG("QemuApplication: sendEvent\n");
-    [super sendEvent: event];
+    if (![cocoaView handleEvent:event]) {
+        [super sendEvent: event];
+    }
 }
 @end
 
@@ -1672,32 +1673,59 @@ static void addRemovableDevicesMenuItems(void)
     qapi_free_BlockInfoList(pointerToFree);
 }
 
-int main (int argc, const char * argv[]) {
+/*
+ * The startup process for the OSX/Cocoa UI is complicated, because
+ * OSX insists that the UI runs on the initial main thread, and so we
+ * need to start a second thread which runs the vl.c qemu_main():
+ *
+ * Initial thread:                    2nd thread:
+ * in main():
+ *  create qemu-main thread
+ *  wait on display_init semaphore
+ *                                    call qemu_main()
+ *                                    ...
+ *                                    in cocoa_display_init():
+ *                                     post the display_init semaphore
+ *                                     wait on app_started semaphore
+ *  create application, menus, etc
+ *  enter OSX run loop
+ * in applicationDidFinishLaunching:
+ *  post app_started semaphore
+ *                                     tell main thread to fullscreen if needed
+ *                                    [...]
+ *                                    run qemu main-loop
+ *
+ * We do this in two stages so that we don't do the creation of the
+ * GUI application menus and so on for command line options like --help
+ * where we want to just print text to stdout and exit immediately.
+ */
 
+static void *call_qemu_main(void *opaque)
+{
+    int status;
+
+    COCOA_DEBUG("Second thread: calling qemu_main()\n");
+    status = qemu_main(gArgc, gArgv, *_NSGetEnviron());
+    COCOA_DEBUG("Second thread: qemu_main() returned, exiting\n");
+    exit(status);
+}
+
+int main (int argc, const char * argv[]) {
+    QemuThread thread;
+
+    COCOA_DEBUG("Entered main()\n");
     gArgc = argc;
     gArgv = (char **)argv;
-    int i;
 
-    /* In case we don't need to display a window, let's not do that */
-    for (i = 1; i < argc; i++) {
-        const char *opt = argv[i];
+    qemu_sem_init(&display_init_sem, 0);
+    qemu_sem_init(&app_started_sem, 0);
 
-        if (opt[0] == '-') {
-            /* Treat --foo the same as -foo.  */
-            if (opt[1] == '-') {
-                opt++;
-            }
-            if (!strcmp(opt, "-h") || !strcmp(opt, "-help") ||
-                !strcmp(opt, "-vnc") ||
-                !strcmp(opt, "-nographic") ||
-                !strcmp(opt, "-version") ||
-                !strcmp(opt, "-curses") ||
-                !strcmp(opt, "-display") ||
-                !strcmp(opt, "-qtest")) {
-                return qemu_main(gArgc, gArgv, *_NSGetEnviron());
-            }
-        }
-    }
+    qemu_thread_create(&thread, "qemu_main", call_qemu_main,
+                       NULL, QEMU_THREAD_DETACHED);
+
+    COCOA_DEBUG("Main thread: waiting for display_init_sem\n");
+    qemu_sem_wait(&display_init_sem);
+    COCOA_DEBUG("Main thread: initializing app\n");
 
     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
 
@@ -1710,12 +1738,24 @@ int main (int argc, const char * argv[]) {
 
     create_initial_menus();
 
+    /*
+     * Create the menu entries which depend on QEMU state (for consoles
+     * and removeable devices). These make calls back into QEMU functions,
+     * which is OK because at this point we know that the second thread
+     * holds the iothread lock and is synchronously waiting for us to
+     * finish.
+     */
+    add_console_menu_entries();
+    addRemovableDevicesMenuItems();
+
     // Create an Application controller
     QemuCocoaAppController *appController = [[QemuCocoaAppController alloc] init];
     [NSApp setDelegate:appController];
 
     // Start the main event loop
+    COCOA_DEBUG("Main thread: entering OSX run loop\n");
     [NSApp run];
+    COCOA_DEBUG("Main thread: left OSX run loop, exiting\n");
 
     [appController release];
     [pool release];
@@ -1733,17 +1773,19 @@ static void cocoa_update(DisplayChangeListener *dcl,
 
     COCOA_DEBUG("qemu_cocoa: cocoa_update\n");
 
-    NSRect rect;
-    if ([cocoaView cdx] == 1.0) {
-        rect = NSMakeRect(x, [cocoaView gscreen].height - y - h, w, h);
-    } else {
-        rect = NSMakeRect(
-            x * [cocoaView cdx],
-            ([cocoaView gscreen].height - y - h) * [cocoaView cdy],
-            w * [cocoaView cdx],
-            h * [cocoaView cdy]);
-    }
-    [cocoaView setNeedsDisplayInRect:rect];
+    dispatch_async(dispatch_get_main_queue(), ^{
+        NSRect rect;
+        if ([cocoaView cdx] == 1.0) {
+            rect = NSMakeRect(x, [cocoaView gscreen].height - y - h, w, h);
+        } else {
+            rect = NSMakeRect(
+                x * [cocoaView cdx],
+                ([cocoaView gscreen].height - y - h) * [cocoaView cdy],
+                w * [cocoaView cdx],
+                h * [cocoaView cdy]);
+        }
+        [cocoaView setNeedsDisplayInRect:rect];
+    });
 
     [pool release];
 }
@@ -1752,9 +1794,19 @@ static void cocoa_switch(DisplayChangeListener *dcl,
                          DisplaySurface *surface)
 {
     NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
+    pixman_image_t *image = surface->image;
 
     COCOA_DEBUG("qemu_cocoa: cocoa_switch\n");
-    [cocoaView switchSurface:surface->image];
+
+    // The DisplaySurface will be freed as soon as this callback returns.
+    // We take a reference to the underlying pixman image here so it does
+    // not disappear from under our feet; the switchSurface method will
+    // deref the old image when it is done with it.
+    pixman_image_ref(image);
+
+    dispatch_async(dispatch_get_main_queue(), ^{
+        [cocoaView switchSurface:image];
+    });
     [pool release];
 }
 
@@ -1766,26 +1818,15 @@ static void cocoa_refresh(DisplayChangeListener *dcl)
     graphic_hw_update(NULL);
 
     if (qemu_input_is_absolute()) {
-        if (![cocoaView isAbsoluteEnabled]) {
-            if ([cocoaView isMouseGrabbed]) {
-                [cocoaView ungrabMouse];
+        dispatch_async(dispatch_get_main_queue(), ^{
+            if (![cocoaView isAbsoluteEnabled]) {
+                if ([cocoaView isMouseGrabbed]) {
+                    [cocoaView ungrabMouse];
+                }
             }
-        }
-        [cocoaView setAbsoluteEnabled:YES];
+            [cocoaView setAbsoluteEnabled:YES];
+        });
     }
-
-    NSDate *distantPast;
-    NSEvent *event;
-    distantPast = [NSDate distantPast];
-    do {
-        event = [NSApp nextEventMatchingMask:NSEventMaskAny untilDate:distantPast
-                        inMode: NSDefaultRunLoopMode dequeue:YES];
-        if (event != nil) {
-            if (![cocoaView handleEvent:event]) {
-                [NSApp sendEvent:event];
-            }
-        }
-    } while(event != nil);
     [pool release];
 }
 
@@ -1806,10 +1847,17 @@ static void cocoa_display_init(DisplayState *ds, DisplayOptions *opts)
 {
     COCOA_DEBUG("qemu_cocoa: cocoa_display_init\n");
 
+    /* Tell main thread to go ahead and create the app and enter the run loop */
+    qemu_sem_post(&display_init_sem);
+    qemu_sem_wait(&app_started_sem);
+    COCOA_DEBUG("cocoa_display_init: app start completed\n");
+
     /* if fullscreen mode is to be used */
     if (opts->has_full_screen && opts->full_screen) {
-        [NSApp activateIgnoringOtherApps: YES];
-        [(QemuCocoaAppController *)[[NSApplication sharedApplication] delegate] toggleFullScreen: nil];
+        dispatch_async(dispatch_get_main_queue(), ^{
+            [NSApp activateIgnoringOtherApps: YES];
+            [(QemuCocoaAppController *)[[NSApplication sharedApplication] delegate] toggleFullScreen: nil];
+        });
     }
 
     dcl = g_malloc0(sizeof(DisplayChangeListener));
@@ -1820,17 +1868,6 @@ static void cocoa_display_init(DisplayState *ds, DisplayOptions *opts)
 
     // register cleanup function
     atexit(cocoa_cleanup);
-
-    /* At this point QEMU has created all the consoles, so we can add View
-     * menu entries for them.
-     */
-    add_console_menu_entries();
-
-    /* Give all removable devices a menu item.
-     * Has to be called after QEMU has started to
-     * find out what removable devices it has.
-     */
-    addRemovableDevicesMenuItems();
 }
 
 static QemuDisplay qemu_display_cocoa = {