diff --git a/src/calibre/gui2/dialogs/authors_edit.py b/src/calibre/gui2/dialogs/authors_edit.py
index 9e088562b9..03a09d00a7 100644
--- a/src/calibre/gui2/dialogs/authors_edit.py
+++ b/src/calibre/gui2/dialogs/authors_edit.py
@@ -29,7 +29,7 @@ class ItemDelegate(QStyledItemDelegate):
         return QStyledItemDelegate.sizeHint(self, *args) + QSize(0, 15)
 
     def setEditorData(self, editor, index):
-        name = unicode(index.data(Qt.DisplayRole).toString())
+        name = unicode(index.data(Qt.DisplayRole) or '')
         editor.setText(name)
         editor.lineEdit().selectAll()
 
diff --git a/src/calibre/gui2/dialogs/book_info.py b/src/calibre/gui2/dialogs/book_info.py
index c86773ed07..86dccc787a 100644
--- a/src/calibre/gui2/dialogs/book_info.py
+++ b/src/calibre/gui2/dialogs/book_info.py
@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 from PyQt5.Qt import (
     QCoreApplication, QModelIndex, QTimer, Qt, pyqtSignal, QWidget,
     QGridLayout, QDialog, QPixmap, QSize, QPalette, QShortcut, QKeySequence,
-    QSplitter, QVBoxLayout, QCheckBox, QPushButton, QIcon, QBrush)
+    QSplitter, QVBoxLayout, QCheckBox, QPushButton, QIcon, QBrush, QUrl)
 from PyQt5.QtWebKitWidgets import QWebView
 
 from calibre.gui2 import gprefs
@@ -103,7 +103,7 @@ class BookInfo(QDialog):
                 pass
 
     def link_clicked(self, qurl):
-        link = unicode(qurl.toString())
+        link = unicode(qurl.toString(QUrl.None))
         self.link_delegate(link)
 
     def done(self, r):
diff --git a/src/calibre/gui2/dialogs/check_library.py b/src/calibre/gui2/dialogs/check_library.py
index d99c12a7be..3afb1079de 100644
--- a/src/calibre/gui2/dialogs/check_library.py
+++ b/src/calibre/gui2/dialogs/check_library.py
@@ -352,7 +352,7 @@ class CheckLibraryDialog(QDialog):
         child_count = tl.childCount()
         for i in range(0, child_count):
             item = tl.child(i)
-            id = item.data(0, Qt.UserRole).toInt()[0]
+            id = int(item.data(0, Qt.UserRole))
             all = self.db.formats(id, index_is_id=True, verify_formats=False)
             all = set([f.strip() for f in all.split(',')]) if all else set()
             valid = self.db.formats(id, index_is_id=True, verify_formats=True)
@@ -365,7 +365,7 @@ class CheckLibraryDialog(QDialog):
         child_count = tl.childCount()
         for i in range(0, child_count):
             item = tl.child(i)
-            id = item.data(0, Qt.UserRole).toInt()[0]
+            id = int(item.data(0, Qt.UserRole))
             self.db.set_has_cover(id, False)
 
     def fix_extra_covers(self):
@@ -373,7 +373,7 @@ class CheckLibraryDialog(QDialog):
         child_count = tl.childCount()
         for i in range(0, child_count):
             item = tl.child(i)
-            id = item.data(0, Qt.UserRole).toInt()[0]
+            id = int(item.data(0, Qt.UserRole))
             self.db.set_has_cover(id, True)
 
     def fix_items(self):
diff --git a/src/calibre/gui2/dialogs/delete_matching_from_device.py b/src/calibre/gui2/dialogs/delete_matching_from_device.py
index 42846b68cb..6f9b9847cd 100644
--- a/src/calibre/gui2/dialogs/delete_matching_from_device.py
+++ b/src/calibre/gui2/dialogs/delete_matching_from_device.py
@@ -110,7 +110,7 @@ class DeleteMatchingFromDeviceDialog(QDialog, Ui_DeleteMatchingFromDeviceDialog)
         for row in range(self.table.rowCount()):
             if self.table.item(row, 0).checkState() == Qt.Unchecked:
                 continue
-            (model, id, path) = self.table.item(row, 0).data(Qt.UserRole).toPyObject()
+            (model, id, path) = self.table.item(row, 0).data(Qt.UserRole)
             path = unicode(path)
             self.result.append((model, id, path))
         return
diff --git a/src/calibre/gui2/dialogs/device_category_editor.py b/src/calibre/gui2/dialogs/device_category_editor.py
index 20f628e70c..4f4758ad98 100644
--- a/src/calibre/gui2/dialogs/device_category_editor.py
+++ b/src/calibre/gui2/dialogs/device_category_editor.py
@@ -87,7 +87,7 @@ class DeviceCategoryEditor(QDialog, Ui_DeviceCategoryEditor):
                 item.setText(item.previous_text())
                 return
         if item.text() != item.initial_text():
-            id_ = item.data(Qt.UserRole).toInt()[0]
+            id_ = int(item.data(Qt.UserRole))
             self.to_rename[id_] = unicode(item.text())
 
     def rename_tag(self):
@@ -113,7 +113,7 @@ class DeviceCategoryEditor(QDialog, Ui_DeviceCategoryEditor):
             return
         row = self.available_tags.row(deletes[0])
         for item in deletes:
-            (id,ign) = item.data(Qt.UserRole).toInt()
+            id = int(item.data(Qt.UserRole))
             self.to_delete.add(id)
             self.available_tags.takeItem(self.available_tags.row(item))
 
diff --git a/src/calibre/gui2/dialogs/duplicates.py b/src/calibre/gui2/dialogs/duplicates.py
index fdb200b8aa..0d1c5580ab 100644
--- a/src/calibre/gui2/dialogs/duplicates.py
+++ b/src/calibre/gui2/dialogs/duplicates.py
@@ -135,7 +135,7 @@ class DuplicatesQuestion(QDialog):
         for i in xrange(self.dup_list.topLevelItemCount()):
             x = self.dup_list.topLevelItem(i)
             if x.checkState(0) == Qt.Checked:
-                yield x.data(0, Qt.UserRole).toPyObject()
+                yield x.data(0, Qt.UserRole)
 
     @property
     def as_text(self):
diff --git a/src/calibre/gui2/dialogs/edit_authors_dialog.py b/src/calibre/gui2/dialogs/edit_authors_dialog.py
index 12bf4aac49..7adf06c99f 100644
--- a/src/calibre/gui2/dialogs/edit_authors_dialog.py
+++ b/src/calibre/gui2/dialogs/edit_authors_dialog.py
@@ -274,7 +274,7 @@ class EditAuthorsDialog(QDialog, Ui_EditAuthorsDialog):
         self.save_state()
         self.result = []
         for row in range(0,self.table.rowCount()):
-            id   = self.table.item(row, 0).data(Qt.UserRole).toInt()[0]
+            id   = int(self.table.item(row, 0).data(Qt.UserRole))
             aut  = unicode(self.table.item(row, 0).text()).strip()
             sort = unicode(self.table.item(row, 1).text()).strip()
             link = unicode(self.table.item(row, 2).text()).strip()
diff --git a/src/calibre/gui2/dialogs/match_books.py b/src/calibre/gui2/dialogs/match_books.py
index 5dd361283d..6c4ff84aff 100644
--- a/src/calibre/gui2/dialogs/match_books.py
+++ b/src/calibre/gui2/dialogs/match_books.py
@@ -168,7 +168,7 @@ class MatchBooks(QDialog, Ui_MatchBooks):
 
     def book_clicked(self, row, column):
         self.book_selected = True
-        id_ = self.books_table.item(row, 0).data(Qt.UserRole).toInt()[0]
+        id_ = int(self.books_table.item(row, 0).data(Qt.UserRole))
         self.current_library_book_id = id_
 
     def book_doubleclicked(self, row, column):
diff --git a/src/calibre/gui2/dialogs/metadata_bulk.py b/src/calibre/gui2/dialogs/metadata_bulk.py
index fde5908a70..e89285ebba 100644
--- a/src/calibre/gui2/dialogs/metadata_bulk.py
+++ b/src/calibre/gui2/dialogs/metadata_bulk.py
@@ -569,12 +569,12 @@ class MetadataBulkDialog(ResizableDialog, Ui_MetadataBulkDialog):
     def s_r_sf_itemdata(self, idx):
         if idx is None:
             idx = self.search_field.currentIndex()
-        return unicode(self.search_field.itemData(idx).toString())
+        return unicode(self.search_field.itemData(idx) or '')
 
     def s_r_df_itemdata(self, idx):
         if idx is None:
             idx = self.destination_field.currentIndex()
-        return unicode(self.destination_field.itemData(idx).toString())
+        return unicode(self.destination_field.itemData(idx) or '')
 
     def s_r_get_field(self, mi, field):
         if field:
diff --git a/src/calibre/gui2/dialogs/quickview.py b/src/calibre/gui2/dialogs/quickview.py
index 553f09b4a8..ff5b8d4ebe 100644
--- a/src/calibre/gui2/dialogs/quickview.py
+++ b/src/calibre/gui2/dialogs/quickview.py
@@ -277,7 +277,7 @@ class Quickview(QDialog, Ui_Quickview):
     def book_doubleclicked(self, row, column):
         if self.no_valid_items:
             return
-        book_id = self.books_table.item(row, self.title_column).data(Qt.UserRole).toInt()[0]
+        book_id = int(self.books_table.item(row, self.title_column).data(Qt.UserRole))
         self.view.select_rows([book_id])
         modifiers = int(QApplication.keyboardModifiers())
         if modifiers in (Qt.CTRL, Qt.SHIFT):
@@ -315,4 +315,4 @@ class Quickview(QDialog, Ui_Quickview):
     # called by the close button
     def reject(self):
         self._close()
-        QDialog.reject(self)
\ No newline at end of file
+        QDialog.reject(self)
diff --git a/src/calibre/gui2/dialogs/select_formats.py b/src/calibre/gui2/dialogs/select_formats.py
index e57da09e49..374c80a13a 100644
--- a/src/calibre/gui2/dialogs/select_formats.py
+++ b/src/calibre/gui2/dialogs/select_formats.py
@@ -8,9 +8,9 @@ __docformat__ = 'restructuredtext en'
 
 
 from PyQt5.Qt import QVBoxLayout, QDialog, QLabel, QDialogButtonBox, Qt, \
-        QAbstractListModel, QVariant, QListView, QSize
+        QAbstractListModel, QListView, QSize
 
-from calibre.gui2 import NONE, file_icon_provider
+from calibre.gui2 import file_icon_provider
 
 class Formats(QAbstractListModel):
 
@@ -28,16 +28,16 @@ class Formats(QAbstractListModel):
         if role == Qt.DisplayRole:
             fmt = self.fmts[row]
             count = self.counts[fmt]
-            return QVariant('%s [%d]'%(fmt.upper(), count))
+            return ('%s [%d]'%(fmt.upper(), count))
         if role == Qt.DecorationRole:
-            return QVariant(self.fi.icon_from_ext(self.fmts[row].lower()))
+            return (self.fi.icon_from_ext(self.fmts[row].lower()))
         if role == Qt.ToolTipRole:
             fmt = self.fmts[row]
             count = self.counts[fmt]
-            return QVariant(
+            return (
                 _('There are %(count)d book(s) with the %(fmt)s format')%dict(
                     count=count, fmt=fmt.upper()))
-        return NONE
+        return None
 
     def flags(self, index):
         return Qt.ItemIsSelectable|Qt.ItemIsEnabled
diff --git a/src/calibre/gui2/dialogs/tag_categories.py b/src/calibre/gui2/dialogs/tag_categories.py
index dcdef073a4..d74aa8f2d6 100644
--- a/src/calibre/gui2/dialogs/tag_categories.py
+++ b/src/calibre/gui2/dialogs/tag_categories.py
@@ -165,7 +165,7 @@ class TagCategories(QDialog, Ui_TagCategories):
             return
         nodes = self.available_items_box.selectedItems() if node is None else [node]
         for node in nodes:
-            index = self.all_items[node.data(Qt.UserRole).toPyObject()].index
+            index = self.all_items[node.data(Qt.UserRole)].index
             if index not in self.applied_items:
                 self.applied_items.append(index)
         self.applied_items.sort(key=lambda x:sort_key(self.all_items[x].name))
@@ -177,7 +177,7 @@ class TagCategories(QDialog, Ui_TagCategories):
     def unapply_tags(self, node=None):
         nodes = self.applied_items_box.selectedItems() if node is None else [node]
         for node in nodes:
-            index = self.all_items[node.data(Qt.UserRole).toPyObject()].index
+            index = self.all_items[node.data(Qt.UserRole)].index
             self.applied_items.remove(index)
         self.display_filtered_categories(None)
 
diff --git a/src/calibre/gui2/dialogs/tag_list_editor.py b/src/calibre/gui2/dialogs/tag_list_editor.py
index 7cdc88e855..28e8ec7772 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor.py
@@ -210,7 +210,7 @@ class TagListEditor(QDialog, Ui_TagListEditor):
                 item.setText(item.previous_text())
                 return
         if item.text() != item.initial_text():
-            id_ = item.data(Qt.UserRole).toInt()[0]
+            id_ = int(item.data(Qt.UserRole))
             self.to_rename[id_] = unicode(item.text())
             orig = self.table.item(item.row(), 2)
             self.table.blockSignals(True)
@@ -240,7 +240,7 @@ class TagListEditor(QDialog, Ui_TagListEditor):
             return
         row = self.table.row(deletes[0])
         for item in deletes:
-            (id,ign) = item.data(Qt.UserRole).toInt()
+            id = int(item.data(Qt.UserRole))
             self.to_delete.add(id)
             self.table.removeRow(self.table.row(item))
 
diff --git a/src/calibre/gui2/dialogs/template_dialog.py b/src/calibre/gui2/dialogs/template_dialog.py
index a939facfbd..ca34c4c31a 100644
--- a/src/calibre/gui2/dialogs/template_dialog.py
+++ b/src/calibre/gui2/dialogs/template_dialog.py
@@ -7,7 +7,7 @@ import json, os, traceback
 
 from PyQt5.Qt import (Qt, QDialog, QDialogButtonBox, QSyntaxHighlighter, QFont,
                       QRegExp, QApplication, QTextCharFormat, QColor, QCursor,
-                      QIcon, QSize, QVariant)
+                      QIcon, QSize)
 
 from calibre import sanitize_file_name_unicode
 from calibre.constants import config_dir
@@ -248,7 +248,7 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
             from calibre.gui2.preferences.coloring import icon_rule_kinds
             for i,tup in enumerate(icon_rule_kinds):
                 txt,val = tup
-                self.icon_kind.addItem(txt, userData=QVariant(val))
+                self.icon_kind.addItem(txt, userData=(val))
                 if val == icon_rule_kind:
                     dex = i
             self.icon_kind.setCurrentIndex(dex)
@@ -426,12 +426,12 @@ class TemplateDialog(QDialog, Ui_TemplateDialog):
                 return
 
             self.rule = (unicode(self.colored_field.itemData(
-                                self.colored_field.currentIndex()).toString()), txt)
+                                self.colored_field.currentIndex()) or ''), txt)
         elif self.iconing:
-            rt = unicode(self.icon_kind.itemData(self.icon_kind.currentIndex()).toString())
+            rt = unicode(self.icon_kind.itemData(self.icon_kind.currentIndex()) or '')
             self.rule = (rt,
                          unicode(self.icon_field.itemData(
-                                self.icon_field.currentIndex()).toString()),
+                                self.icon_field.currentIndex()) or ''),
                          txt)
         else:
             self.rule = ('', txt)
diff --git a/src/calibre/gui2/dialogs/user_profiles.py b/src/calibre/gui2/dialogs/user_profiles.py
index d5ed0bd2bc..4ba0431a52 100644
--- a/src/calibre/gui2/dialogs/user_profiles.py
+++ b/src/calibre/gui2/dialogs/user_profiles.py
@@ -3,14 +3,14 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time, os
 
-from PyQt5.Qt import (QUrl, QAbstractListModel, Qt, QVariant, QFont)
+from PyQt5.Qt import (QUrl, QAbstractListModel, Qt, QFont)
 
 from calibre.web.feeds.recipes import compile_recipe, custom_recipes
 from calibre.web.feeds.news import AutomaticNewsRecipe
 from calibre.gui2.dialogs.user_profiles_ui import Ui_Dialog
 from calibre.gui2 import (
     error_dialog, question_dialog, open_url, choose_files, ResizableDialog,
-    NONE, open_local_file)
+    open_local_file)
 from calibre.gui2.widgets import PythonHighlighter
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils.icu import sort_key
@@ -48,8 +48,8 @@ class CustomRecipeModel(QAbstractListModel):
         if role == Qt.DisplayRole:
             ans = self.title(index)
             if ans is not None:
-                return QVariant(ans)
-        return NONE
+                return (ans)
+        return None
 
     def replace_by_title(self, title, script):
         urn = None
@@ -330,8 +330,8 @@ class %(classname)s(%(base_class)s):
         if not items:
             return
         item = items[-1]
-        id_ = unicode(item.data(Qt.UserRole).toString())
-        title = unicode(item.data(Qt.DisplayRole).toString()).rpartition(' [')[0]
+        id_ = unicode(item.data(Qt.UserRole) or '')
+        title = unicode(item.data(Qt.DisplayRole) or '').rpartition(' [')[0]
         profile = get_builtin_recipe_by_id(id_, download_recipe=True)
         if profile is None:
             raise Exception('Something weird happened')