diff --git a/src/calibre/gui2/actions/embed.py b/src/calibre/gui2/actions/embed.py
index b7c00b18ac..f564875afa 100644
--- a/src/calibre/gui2/actions/embed.py
+++ b/src/calibre/gui2/actions/embed.py
@@ -8,7 +8,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 
 from functools import partial
 
-from PyQt4.Qt import QTimer, QProgressDialog, Qt
+from PyQt5.Qt import QTimer, QProgressDialog, Qt
 
 from calibre import force_unicode
 from calibre.gui2 import warning_dialog
diff --git a/src/calibre/gui2/tweak_book/preferences.py b/src/calibre/gui2/tweak_book/preferences.py
index 9b0637c564..d43575b3c8 100644
--- a/src/calibre/gui2/tweak_book/preferences.py
+++ b/src/calibre/gui2/tweak_book/preferences.py
@@ -396,13 +396,13 @@ class ToolbarSettings(QWidget):
         prefs = prefs or tprefs
         val = self.original_settings = {}
         for i in xrange(1, self.bars.count()):
-            name = unicode(self.bars.itemData(i).toString())
+            name = unicode(self.bars.itemData(i) or '')
             val[name] = copy(prefs[name])
         self.current_settings = deepcopy(val)
 
     @property
     def current_name(self):
-        return unicode(self.bars.itemData(self.bars.currentIndex()).toString())
+        return unicode(self.bars.itemData(self.bars.currentIndex()) or '')
 
     def build_lists(self):
         from calibre.gui2.tweak_book.plugin import plugin_toolbar_actions
@@ -482,7 +482,7 @@ class ToolbarSettings(QWidget):
             s = self.current_settings[self.current_name]
         except KeyError:
             return
-        names = [unicode(i.data(Qt.UserRole).toString()) for i in self.available.selectedItems()]
+        names = [unicode(i.data(Qt.UserRole) or '') for i in self.available.selectedItems()]
         if not names:
             return
         for n in names: