diff --git a/setup/installer/osx/app/main.py b/setup/installer/osx/app/main.py
index 101ffe0efd..3aa08e4f32 100644
--- a/setup/installer/osx/app/main.py
+++ b/setup/installer/osx/app/main.py
@@ -603,7 +603,7 @@ class Py2App(object):
                     except:
                         self.warn('WARNING: Failed to byte-compile', y)
 
-    def create_app_clone(self, name, specialise_plist):
+    def create_app_clone(self, name, specialise_plist, remove_doc_types=True):
         info('\nCreating ' + name)
         cc_dir = os.path.join(self.contents_dir, name, 'Contents')
         exe_dir = join(cc_dir, 'MacOS')
@@ -614,7 +614,8 @@ class Py2App(object):
             if x == 'Info.plist':
                 plist = plistlib.readPlist(join(self.contents_dir, x))
                 specialise_plist(plist)
-                plist.pop('CFBundleDocumentTypes')
+                if remove_doc_types:
+                    plist.pop('CFBundleDocumentTypes')
                 exe = plist['CFBundleExecutable']
                 # We cannot symlink the bundle executable as if we do,
                 # codesigning fails
@@ -642,7 +643,8 @@ class Py2App(object):
 
     @flush
     def create_gui_apps(self):
-        def specialise_plist(launcher, plist):
+        from calibre.customize.ui import all_input_formats
+        def specialise_plist(launcher, remove_types, plist):
             plist['CFBundleDisplayName'] = plist['CFBundleName'] = {
                 'ebook-viewer':'E-book Viewer', 'ebook-edit':'Edit Book', 'calibre-debug': 'calibre (debug)',
             }[launcher]
@@ -650,8 +652,14 @@ class Py2App(object):
             if launcher != 'calibre-debug':
                 plist['CFBundleIconFile'] = launcher + '.icns'
             plist['CFBundleIdentifier'] = 'com.calibre-ebook.' + launcher
+            if not remove_types:
+                input_formats = sorted(all_input_formats())
+                e = plist['CFBundleDocumentTypes'][0]
+                exts = 'epub azw3'.split() if launcher == 'ebook-edit' else input_formats
+                e['CFBundleTypeExtensions'] = exts
         for launcher in ('ebook-viewer', 'ebook-edit', 'calibre-debug'):
-            self.create_app_clone(launcher + '.app', partial(specialise_plist, launcher))
+            remove_types = launcher == 'calibre-debug'
+            self.create_app_clone(launcher + '.app', partial(specialise_plist, launcher, remove_types), remove_doc_types=remove_types)
 
     @flush
     def copy_site(self):
diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index cc15f38be5..6fa8dd8a66 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -7,7 +7,7 @@ from threading import Thread
 from collections import namedtuple
 
 from PyQt5.Qt import (
-    QApplication, Qt, QIcon, QTimer, QByteArray, QSize, QTime,
+    QApplication, Qt, QIcon, QTimer, QByteArray, QSize, QTime, QObject,
     QPropertyAnimation, QUrl, QInputDialog, QAction, QModelIndex, pyqtSignal)
 
 from calibre.gui2.viewer.ui import Main as MainWindow
@@ -97,7 +97,7 @@ class EbookViewer(MainWindow):
     msg_from_anotherinstance = pyqtSignal(object)
 
     def __init__(self, pathtoebook=None, debug_javascript=False, open_at=None,
-                 start_in_fullscreen=False, continue_reading=False, listener=None):
+                 start_in_fullscreen=False, continue_reading=False, listener=None, file_events=()):
         MainWindow.__init__(self, debug_javascript)
         self.view.magnification_changed.connect(self.magnification_changed)
         self.closed = False
@@ -184,11 +184,14 @@ class EbookViewer(MainWindow):
         self.set_bookmarks([])
         self.load_theme_menu()
 
+        file_events.got_file.connect(self.load_ebook)
         if pathtoebook is not None:
             f = functools.partial(self.load_ebook, pathtoebook, open_at=open_at)
             QTimer.singleShot(50, f)
         elif continue_reading:
             QTimer.singleShot(50, self.continue_reading)
+        else:
+            QTimer.singleShot(50, file_events.flush)
         self.window_mode_changed = None
         self.toggle_toolbar_action = QAction(_('Show/hide controls'), self)
         self.toggle_toolbar_action.setCheckable(True)
@@ -228,6 +231,10 @@ class EbookViewer(MainWindow):
         t.timeout.connect(self.hide_cursor)
         t.start()
 
+    def process_file_events(self):
+        if self.file_events:
+            self.load_ebook(self.file_events[-1])
+
     def eventFilter(self, obj, ev):
         if ev.type() == ev.MouseMove:
             if self.cursor_hidden:
@@ -1153,6 +1160,24 @@ def ensure_single_instance(args, open_at):
     listener = create_listener()
     return listener
 
+class EventAccumulator(QObject):
+
+    got_file = pyqtSignal(object)
+
+    def __init__(self):
+        QObject.__init__(self)
+        self.events = []
+
+    def __call__(self, paths):
+        for path in paths:
+            if os.path.exists(path):
+                self.events.append(path)
+                self.got_file.emit(path)
+
+    def flush(self):
+        if self.events:
+            self.got_file.emit(self.events[-1])
+            self.events = []
 
 def main(args=sys.argv):
     # Ensure viewer can continue to function if GUI is closed
@@ -1164,7 +1189,9 @@ def main(args=sys.argv):
     open_at = float(opts.open_at.replace(',', '.')) if opts.open_at else None
     listener = None
     override = 'calibre-ebook-viewer' if islinux else None
+    acc = EventAccumulator()
     app = Application(args, override_program_name=override, color_prefs=vprefs)
+    app.file_event_hook = acc
     app.load_builtin_fonts()
     app.setWindowIcon(QIcon(I('viewer.png')))
     QApplication.setOrganizationName(ORG_NAME)
@@ -1180,7 +1207,7 @@ def main(args=sys.argv):
 
     main = EbookViewer(args[1] if len(args) > 1 else None,
             debug_javascript=opts.debug_javascript, open_at=open_at, continue_reading=opts.continue_reading,
-                       start_in_fullscreen=opts.full_screen, listener=listener)
+                       start_in_fullscreen=opts.full_screen, listener=listener, file_events=acc)
     app.installEventFilter(main)
     # This is needed for paged mode. Without it, the first document that is
     # loaded will have extra blank space at the bottom, as