diff --git a/src/calibre/debug.py b/src/calibre/debug.py
index 8cc125b118..e1c3e1809e 100644
--- a/src/calibre/debug.py
+++ b/src/calibre/debug.py
@@ -23,6 +23,12 @@ Run an embedded python interpreter.
                       help='Debug the specified device driver.')
     parser.add_option('-g', '--gui',  default=False, action='store_true',
                       help='Run the GUI',)
+    parser.add_option('--gui-debug',  default=None,
+                      help='Run the GUI with a debug console, logging to the'
+                      ' specified path',)
+    parser.add_option('--show-gui-debug',  default=None,
+                      help='Display the specified log file.',)
+
     parser.add_option('-w', '--viewer',  default=False, action='store_true',
                       help='Run the ebook viewer',)
     parser.add_option('--paths', default=False, action='store_true',
@@ -135,7 +141,28 @@ def add_simple_plugin(path_to_plugin):
     os.chdir(odir)
     shutil.rmtree(tdir)
 
-
+def run_debug_gui(logpath):
+    import time, platform
+    time.sleep(3) # Give previous GUI time to shutdown fully and release locks
+    from calibre.constants import __appname__, __version__, isosx
+    print __appname__, _('Debug log')
+    print __appname__, __version__
+    print platform.platform()
+    print platform.system()
+    print platform.system_alias(platform.system(), platform.release(),
+            platform.version())
+    print 'Python', platform.python_version()
+    try:
+        if iswindows:
+            print 'Windows:', platform.win32_ver()
+        elif isosx:
+            print 'OSX:', platform.mac_ver()
+        else:
+            print 'Linux:', platform.linux_distribution()
+    except:
+        pass
+    from calibre.gui2.main import main
+    main(['__CALIBRE_GUI_DEBUG__', logpath])
 
 def main(args=sys.argv):
     from calibre.constants import debug
@@ -154,6 +181,20 @@ def main(args=sys.argv):
     if opts.gui:
         from calibre.gui2.main import main
         main(['calibre'])
+    elif opts.gui_debug is not None:
+        run_debug_gui(opts.gui_debug)
+    elif opts.show_gui_debug:
+        import time, re
+        time.sleep(1)
+        from calibre.gui2 import open_local_file
+        if iswindows:
+            with open(opts.show_gui_debug, 'r+b') as f:
+                raw = f.read()
+                raw = re.sub('(?<!\r)\n', '\r\n', raw)
+                f.seek(0)
+                f.truncate()
+                f.write(raw)
+        open_local_file(opts.show_gui_debug)
     elif opts.viewer:
         from calibre.gui2.viewer.main import main
         vargs = ['ebook-viewer', '--debug-javascript']
diff --git a/src/calibre/gui2/actions/preferences.py b/src/calibre/gui2/actions/preferences.py
index be536ca4e4..f1fe06c43d 100644
--- a/src/calibre/gui2/actions/preferences.py
+++ b/src/calibre/gui2/actions/preferences.py
@@ -10,6 +10,7 @@ from PyQt4.Qt import QIcon, QMenu, Qt
 from calibre.gui2.actions import InterfaceAction
 from calibre.gui2.preferences.main import Preferences
 from calibre.gui2 import error_dialog
+from calibre.constants import DEBUG
 
 class PreferencesAction(InterfaceAction):
 
@@ -22,6 +23,10 @@ class PreferencesAction(InterfaceAction):
         pm.addAction(QIcon(I('config.png')), _('Preferences'), self.do_config)
         pm.addAction(QIcon(I('wizard.png')), _('Run welcome wizard'),
                 self.gui.run_wizard)
+        if not DEBUG:
+            pm.addSeparator()
+            pm.addAction(QIcon(I('debug.png')), _('Restart in debug mode'),
+                self.debug_restart)
         self.qaction.setMenu(pm)
         self.preferences_menu = pm
         for x in (self.gui.preferences_action, self.qaction):
@@ -44,4 +49,6 @@ class PreferencesAction(InterfaceAction):
         d.run_wizard_requested.connect(self.gui.run_wizard,
                 type=Qt.QueuedConnection)
 
+    def debug_restart(self, *args):
+        self.gui.quit(restart=True, debug_on_restart=True)
 
diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 4da06b22ae..d355fe600e 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -135,9 +135,10 @@ class GuiRunner(QObject):
     '''Make sure an event loop is running before starting the main work of
     initialization'''
 
-    def __init__(self, opts, args, actions, listener, app):
+    def __init__(self, opts, args, actions, listener, app, gui_debug=None):
         self.startup_time = time.time()
         self.opts, self.args, self.listener, self.app = opts, args, listener, app
+        self.gui_debug = gui_debug
         self.actions = actions
         self.main = None
         QObject.__init__(self)
@@ -148,7 +149,7 @@ class GuiRunner(QObject):
 
     def start_gui(self):
         from calibre.gui2.ui import Main
-        main = Main(self.opts)
+        main = Main(self.opts, gui_debug=self.gui_debug)
         if self.splash_screen is not None:
             self.splash_screen.showMessage(_('Initializing user interface...'))
             self.splash_screen.finish(main)
@@ -249,34 +250,56 @@ class GuiRunner(QObject):
 
         self.initialize_db()
 
+def run_in_debug_mode(logpath=None):
+    e = sys.executable if getattr(sys, 'frozen', False) else sys.argv[0]
+    import tempfile, subprocess
+    fd, logpath = tempfile.mkstemp('.txt')
 
+    if hasattr(sys, 'frameworks_dir'):
+        base = os.path.dirname(sys.frameworks_dir)
+        if 'console.app' not in base:
+            base = os.path.join(base, 'console.app', 'Contents')
+        exe = os.path.basename(e)
+        exe = os.path.join(base, 'MacOS', exe+'-debug')
+    else:
+        base, ext = os.path.splitext(e)
+        exe = base + '-debug' + ext
+    print 'Starting debug executable:', exe
+    subprocess.Popen([exe, '--gui-debug', logpath], stdout=fd, stderr=fd)
 
-def run_gui(opts, args, actions, listener, app):
+def run_gui(opts, args, actions, listener, app, gui_debug=None):
     initialize_file_icon_provider()
     if not dynamic.get('welcome_wizard_was_run', False):
         from calibre.gui2.wizard import wizard
         wizard().exec_()
         dynamic.set('welcome_wizard_was_run', True)
-    runner = GuiRunner(opts, args, actions, listener, app)
+    runner = GuiRunner(opts, args, actions, listener, app, gui_debug=gui_debug)
     ret = app.exec_()
     if getattr(runner.main, 'run_wizard_b4_shutdown', False):
         from calibre.gui2.wizard import wizard
         wizard().exec_()
     if getattr(runner.main, 'restart_after_quit', False):
         e = sys.executable if getattr(sys, 'frozen', False) else sys.argv[0]
-        print 'Restarting with:', e, sys.argv
-        if hasattr(sys, 'frameworks_dir'):
-            app = os.path.dirname(os.path.dirname(sys.frameworks_dir))
-            import subprocess
-            subprocess.Popen('sleep 3s; open '+app, shell=True)
+        if getattr(runner.main, 'debug_on_restart', False):
+            run_in_debug_mode()
         else:
-            os.execvp(e, sys.argv)
+            print 'Restarting with:', e, sys.argv
+            if hasattr(sys, 'frameworks_dir'):
+                app = os.path.dirname(os.path.dirname(sys.frameworks_dir))
+                import subprocess
+                subprocess.Popen('sleep 3s; open '+app, shell=True)
+            else:
+                os.execvp(e, sys.argv)
     else:
         if iswindows:
             try:
                 runner.main.system_tray_icon.hide()
             except:
                 pass
+    if runner.main.gui_debug is not None:
+        e = sys.executable if getattr(sys, 'frozen', False) else sys.argv[0]
+        import subprocess
+        subprocess.Popen([e, '--show-gui-debug', runner.main.gui_debug])
     return ret
 
 def cant_start(msg=_('If you are sure it is not running')+', ',
@@ -317,6 +340,11 @@ def communicate(args):
 
 
 def main(args=sys.argv):
+    gui_debug = None
+    if args[0] == '__CALIBRE_GUI_DEBUG__':
+        gui_debug = args[1]
+        args = ['calibre']
+
     app, opts, args, actions = init_qt(args)
     from calibre.utils.lock import singleinstance
     from multiprocessing.connection import Listener
@@ -333,9 +361,11 @@ def main(args=sys.argv):
             except socket.error:
                 cant_start()
             else:
-                return run_gui(opts, args, actions, listener, app)
+                return run_gui(opts, args, actions, listener, app,
+                        gui_debug=gui_debug)
         else:
-            return run_gui(opts, args, actions, listener, app)
+            return run_gui(opts, args, actions, listener, app,
+                    gui_debug=gui_debug)
     otherinstance = False
     try:
         listener = Listener(address=ADDRESS)
@@ -345,8 +375,7 @@ def main(args=sys.argv):
         # On windows only singleinstance can be trusted
         otherinstance = True if iswindows else False
     if not otherinstance:
-        sys.setcheckinterval(50) # Make GUI more responsive
-        return run_gui(opts, args, actions, listener, app)
+        return run_gui(opts, args, actions, listener, app, gui_debug=gui_debug)
 
     communicate(args)
 
diff --git a/src/calibre/gui2/ui.py b/src/calibre/gui2/ui.py
index 219a76bceb..dd3925e732 100644
--- a/src/calibre/gui2/ui.py
+++ b/src/calibre/gui2/ui.py
@@ -96,10 +96,11 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
     'The main GUI'
 
 
-    def __init__(self, opts, parent=None):
+    def __init__(self, opts, parent=None, gui_debug=None):
         MainWindow.__init__(self, opts, parent)
         self.opts = opts
         self.device_connected = None
+        self.gui_debug = gui_debug
         acmap = OrderedDict()
         for action in interface_actions():
             ac = action.load_actual_plugin(self)
@@ -261,6 +262,14 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
         for ac in self.iactions.values():
             ac.initialization_complete()
 
+        if show_gui and self.gui_debug is not None:
+            info_dialog(self, _('Debug mode'), '<p>' +
+                    _('You have started calibre in debug mode. After you '
+                        'quit calibre, the debug log will be available in '
+                        'the file: %s<p>The '
+                        'log will be displayed automatically.')%self.gui_debug, show=True)
+
+
     def start_content_server(self):
         from calibre.library.server.main import start_threaded_server
         from calibre.library.server import server_config
@@ -495,7 +504,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
         dynamic.set('sort_history', self.library_view.model().sort_history)
         self.save_layout_state()
 
-    def quit(self, checked=True, restart=False):
+    def quit(self, checked=True, restart=False, debug_on_restart=False):
         if not self.confirm_quit():
             return
         try:
@@ -503,6 +512,7 @@ class Main(MainWindow, MainWindowMixin, DeviceMixin, EmailMixin, # {{{
         except:
             pass
         self.restart_after_quit = restart
+        self.debug_on_restart = debug_on_restart
         QApplication.instance().quit()
 
     def donate(self, *args):