diff --git a/src/calibre/gui2/preferences/__init__.py b/src/calibre/gui2/preferences/__init__.py
index ee882f2d9e..273e8073ee 100644
--- a/src/calibre/gui2/preferences/__init__.py
+++ b/src/calibre/gui2/preferences/__init__.py
@@ -23,6 +23,10 @@ class AbortCommit(Exception):
     pass
 
 
+class AbortInitialize(Exception):
+    pass
+
+
 class ConfigWidgetInterface(object):
 
     '''
@@ -59,7 +63,8 @@ class ConfigWidgetInterface(object):
     def initialize(self):
         '''
         Should set all config values to their initial values (the values
-        stored in the config files).
+        stored in the config files). A "return" statement is optional. Return
+        False if the dialog is not to be shown.
         '''
         raise NotImplementedError()
 
diff --git a/src/calibre/gui2/preferences/main.py b/src/calibre/gui2/preferences/main.py
index dbd74e8afa..fec9771ef2 100644
--- a/src/calibre/gui2/preferences/main.py
+++ b/src/calibre/gui2/preferences/main.py
@@ -6,22 +6,26 @@ __license__   = 'GPL v3'
 __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
-import textwrap, re
-from functools import partial
+import re
+import textwrap
 from collections import OrderedDict
-
+from functools import partial
 from qt.core import (
-    Qt, QIcon, QFont, QWidget, QScrollArea, QStackedWidget, QVBoxLayout,
-    QLabel, QFrame, QToolBar, QSize, pyqtSignal, QDialogButtonBox,
-    QHBoxLayout, QDialog, QSizePolicy, QPainter, QTextLayout, QPointF,
-    QStatusTipEvent, QApplication, QTabWidget)
+    QApplication, QDialog, QDialogButtonBox, QFont, QFrame, QHBoxLayout, QIcon,
+    QLabel, QPainter, QPointF, QScrollArea, QSize, QSizePolicy, QStackedWidget,
+    QStatusTipEvent, Qt, QTabWidget, QTextLayout, QToolBar, QVBoxLayout, QWidget,
+    pyqtSignal
+)
 
 from calibre.constants import __appname__, __version__, islinux
-from calibre.gui2 import (gprefs, min_available_height, available_width,
-    show_restart_warning)
-from calibre.gui2.dialogs.message_box import Icon
-from calibre.gui2.preferences import init_gui, AbortCommit, get_plugin
 from calibre.customize.ui import preferences_plugins
+from calibre.gui2 import (
+    available_width, gprefs, min_available_height, show_restart_warning
+)
+from calibre.gui2.dialogs.message_box import Icon
+from calibre.gui2.preferences import (
+    AbortCommit, AbortInitialize, get_plugin, init_gui
+)
 from polyglot.builtins import unicode_type
 
 ICON_SIZE = 32
@@ -310,7 +314,10 @@ class Preferences(QDialog):
     def show_plugin(self, plugin):
         self.showing_widget = plugin.create_widget(self.scroll_area)
         self.showing_widget.genesis(self.gui)
-        self.showing_widget.initialize()
+        try:
+            self.showing_widget.initialize()
+        except AbortInitialize:
+            return
         self.set_tooltips_for_labels()
         self.scroll_area.setWidget(self.showing_widget)
         self.stack.setCurrentIndex(1)
@@ -425,8 +432,8 @@ class Preferences(QDialog):
 
 
 if __name__ == '__main__':
-    from calibre.gui_launch import init_dbus
     from calibre.gui2 import Application
+    from calibre.gui_launch import init_dbus
     init_dbus()
     app = Application([])
     app
diff --git a/src/calibre/gui2/preferences/template_functions.py b/src/calibre/gui2/preferences/template_functions.py
index 0c5fcfe036..5bcaa1ef34 100644
--- a/src/calibre/gui2/preferences/template_functions.py
+++ b/src/calibre/gui2/preferences/template_functions.py
@@ -2,12 +2,14 @@
 # vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
 # License: GPLv3 Copyright: 2010, Kovid Goyal <kovid at kovidgoyal.net>
 
-import copy, json, traceback
-from qt.core import QDialogButtonBox, QDialog
+import copy
+import json
+import traceback
+from qt.core import QDialog, QDialogButtonBox
 
-from calibre.gui2 import error_dialog, warning_dialog
+from calibre.gui2 import error_dialog, question_dialog, warning_dialog
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
-from calibre.gui2.preferences import ConfigWidgetBase, test_widget
+from calibre.gui2.preferences import AbortInitialize, ConfigWidgetBase, test_widget
 from calibre.gui2.preferences.template_functions_ui import Ui_Form
 from calibre.gui2.widgets import PythonHighlighter
 from calibre.utils.formatter_functions import (
@@ -149,9 +151,18 @@ class ConfigWidget(ConfigWidgetBase, Ui_Form):
         self.builtins = formatter_functions().get_builtins_and_aliases()
 
         self.st_funcs = {}
-        for v in self.db.prefs.get('user_template_functions', []):
-            if not function_pref_is_python(v):
-                self.st_funcs.update({function_pref_name(v):compile_user_function(*v)})
+        try:
+            for v in self.db.prefs.get('user_template_functions', []):
+                if not function_pref_is_python(v):
+                    self.st_funcs.update({function_pref_name(v):compile_user_function(*v)})
+        except:
+            if question_dialog(self, _('Template functions'),
+                    _('The template functions saved in the library are corrupt. '
+                      "Do you want to delete them? Answering 'Yes' will delete all "
+                      "the functions."), det_msg=traceback.format_exc(),
+                               show_copy_button=True):
+                self.db.prefs['user_template_functions'] = []
+            raise AbortInitialize()
 
         self.build_function_names_box()
         self.function_name.currentIndexChanged[native_string_type].connect(self.function_index_changed)