diff --git a/src/calibre/constants.py b/src/calibre/constants.py
index dc1fa8cf9b..75e6b28095 100644
--- a/src/calibre/constants.py
+++ b/src/calibre/constants.py
@@ -254,8 +254,8 @@ class ExtensionsImporter:
         if iswindows:
             extra = ('winutil', 'wpd', 'winfonts')
         elif ismacos:
-            extra = ('usbobserver', 'cocoa')
-        elif isfreebsd or ishaiku or islinux or ismacos:
+            extra = ('usbobserver', 'cocoa', 'libusb', 'libmtp')
+        elif isfreebsd or ishaiku or islinux:
             extra = ('libusb', 'libmtp')
         else:
             extra = ()
diff --git a/src/calibre/devices/mtp/unix/driver.py b/src/calibre/devices/mtp/unix/driver.py
index 9ab7502041..460ad2d92d 100644
--- a/src/calibre/devices/mtp/unix/driver.py
+++ b/src/calibre/devices/mtp/unix/driver.py
@@ -11,7 +11,7 @@ from collections import namedtuple
 from functools import partial
 
 from calibre import prints, as_unicode, force_unicode
-from calibre.constants import plugins, islinux, ismacos
+from calibre.constants import islinux, ismacos
 from calibre.ptempfile import SpooledTemporaryFile
 from calibre.devices.errors import OpenFailed, DeviceError, BlacklistedDevice, OpenActionNeeded
 from calibre.devices.mtp.base import MTPDeviceBase, synchronous, debug
@@ -52,9 +52,8 @@ class MTP_DEVICE(MTPDeviceBase):
             from calibre.devices.mtp.unix.sysfs import MTPDetect
             self._is_device_mtp = MTPDetect()
         if ismacos and 'osx' in self.supported_platforms:
-            self.usbobserver, err = plugins['usbobserver']
-            if err:
-                raise RuntimeError(err)
+            from calibre_extensions import usbobserver
+            self.usbobserver = usbobserver
             self._is_device_mtp = self.osx_is_device_mtp
 
     def is_device_mtp(self, d, debug=None):
@@ -128,9 +127,7 @@ class MTP_DEVICE(MTPDeviceBase):
             return True
         p = partial(prints, file=output)
         if self.libmtp is None:
-            err = plugins['libmtp'][1]
-            if not err:
-                err = 'startup() not called on this device driver'
+            err = 'startup() not called on this device driver'
             p(err)
             return False
         devs = [d for d in devices_on_system if
@@ -190,12 +187,14 @@ class MTP_DEVICE(MTPDeviceBase):
 
     @synchronous
     def startup(self):
-        p = plugins['libmtp']
-        self.libmtp = p[0]
-        if self.libmtp is None:
+        try:
+            from calibre_extensions import libmtp
+        except Exception as err:
             print('Failed to load libmtp, MTP device detection disabled')
-            print(p[1])
+            print(err)
+            self.libmtp = None
         else:
+            self.libmtp = libmtp
             self.known_devices = frozenset(self.libmtp.known_devices())
 
             for x in vars(self.libmtp):
diff --git a/src/calibre/gui2/__init__.py b/src/calibre/gui2/__init__.py
index f75cf04fd1..25daf9862c 100644
--- a/src/calibre/gui2/__init__.py
+++ b/src/calibre/gui2/__init__.py
@@ -26,7 +26,7 @@ from calibre import as_unicode, prints
 from calibre.constants import (
     DEBUG, __appname__ as APP_UID, __version__, config_dir, filesystem_encoding,
     is_running_from_develop, isbsd, isfrozen, islinux, ismacos, iswindows, isxp,
-    plugins, plugins_loc
+    plugins_loc
 )
 from calibre.ebooks.metadata import MetaInformation
 from calibre.gui2.linux_file_dialogs import (
@@ -881,9 +881,8 @@ class Application(QApplication):
             args.extend(['-platformpluginpath', plugins_loc, '-platform', 'headless'])
         self.headless = headless
         qargs = [i.encode('utf-8') if isinstance(i, unicode_type) else i for i in args]
-        self.pi, pi_err = plugins['progress_indicator']
-        if pi_err:
-            raise RuntimeError('Failed to load the progress_indicator C extension, with error: {}'.format(pi_err))
+        from calibre_extensions import progress_indicator
+        self.pi = progress_indicator
         if not ismacos and not headless:
             # On OS X high dpi scaling is turned on automatically by the OS, so we dont need to set it explicitly
             setup_hidpi()
@@ -899,7 +898,8 @@ class Application(QApplication):
         if hasattr(sh, 'setShowShortcutsInContextMenus'):
             sh.setShowShortcutsInContextMenus(True)
         if ismacos:
-            plugins['cocoa'][0].disable_cocoa_ui_elements()
+            from calibre_extensions.cocoa import disable_cocoa_ui_elements
+            disable_cocoa_ui_elements()
         self.setAttribute(Qt.AA_UseHighDpiPixmaps)
         self.setAttribute(Qt.AA_SynthesizeTouchForUnhandledMouseEvents, False)
         try:
@@ -977,10 +977,8 @@ class Application(QApplication):
             self.aboutToQuit.connect(self.flush_clipboard)
 
         if ismacos:
-            cocoa, err = plugins['cocoa']
-            if err:
-                raise RuntimeError('Failed to load cocoa plugin with error: {}'.format(err))
-            cft = cocoa.cursor_blink_time()
+            from calibre_extensions.cocoa import cursor_blink_time
+            cft = cursor_blink_time()
             if cft >= 0:
                 self.setCursorFlashTime(int(cft))
 
@@ -1134,7 +1132,8 @@ class Application(QApplication):
             icon_map[getattr(QStyle, 'SP_'+k)] = v
         transient_scroller = 0
         if ismacos:
-            transient_scroller = plugins['cocoa'][0].transient_scroller()
+            from calibre_extensions.cocoa import transient_scroller
+            transient_scroller = transient_scroller()
         icon_map[QStyle.SP_CustomBase + 1] = I('close-for-light-theme.png')
         icon_map[QStyle.SP_CustomBase + 2] = I('close-for-dark-theme.png')
         self.pi.load_style(icon_map, transient_scroller)
@@ -1491,8 +1490,9 @@ def set_app_uid(val):
 
 
 def add_to_recent_docs(path):
+    from calibre_extensions import winutil
     app = QApplication.instance()
-    plugins['winutil'][0].add_to_recent_docs(unicode_type(path), app.windows_app_uid)
+    winutil.add_to_recent_docs(unicode_type(path), app.windows_app_uid)
 
 
 def windows_is_system_dark_mode_enabled():