diff --git a/src/calibre/gui2/library/delegates.py b/src/calibre/gui2/library/delegates.py
index ae40352aee..c1b4248c26 100644
--- a/src/calibre/gui2/library/delegates.py
+++ b/src/calibre/gui2/library/delegates.py
@@ -15,7 +15,7 @@ from calibre.gui2 import UNDEFINED_QDATETIME, error_dialog, rating_font
 from calibre.constants import iswindows
 from calibre.gui2.widgets import EnLineEdit
 from calibre.gui2.complete2 import EditWithComplete
-from calibre.utils.date import now, format_date, qt_to_dt
+from calibre.utils.date import now, format_date, qt_to_dt, is_date_undefined
 from calibre.utils.config import tweaks
 from calibre.utils.formatter import validation_formatter
 from calibre.utils.icu import sort_key
@@ -91,10 +91,10 @@ class DateDelegate(QStyledItemDelegate):  # {{{
             self.format = default_format
 
     def displayText(self, val, locale):
-        d = val.toDateTime()
-        if d <= UNDEFINED_QDATETIME:
+        d = qt_to_dt(val.toDateTime())
+        if is_date_undefined(d):
             return ''
-        return format_date(qt_to_dt(d, as_utc=False), self.format)
+        return format_date(d, self.format)
 
     def createEditor(self, parent, option, index):
         return DateTimeEdit(parent, self.format)
@@ -110,17 +110,17 @@ class PubDateDelegate(QStyledItemDelegate):  # {{{
             self.format = 'MMM yyyy'
 
     def displayText(self, val, locale):
-        d = val.toDateTime()
-        if d <= UNDEFINED_QDATETIME:
+        d = qt_to_dt(val.toDateTime())
+        if is_date_undefined(d):
             return ''
-        return format_date(qt_to_dt(d, as_utc=False), self.format)
+        return format_date(d, self.format)
 
     def createEditor(self, parent, option, index):
         return DateTimeEdit(parent, self.format)
 
     def setEditorData(self, editor, index):
         val = index.data(Qt.EditRole).toDate()
-        if val == UNDEFINED_QDATETIME.date():
+        if is_date_undefined(val):
             val = QDate(2000, 1, 1)
         editor.setDate(val)
 
@@ -234,10 +234,10 @@ class CcDateDelegate(QStyledItemDelegate):  # {{{
             self.format = format
 
     def displayText(self, val, locale):
-        d = val.toDateTime()
-        if d <= UNDEFINED_QDATETIME:
+        d = qt_to_dt(val.toDateTime())
+        if is_date_undefined(d):
             return ''
-        return format_date(qt_to_dt(d, as_utc=False), self.format)
+        return format_date(d, self.format)
 
     def createEditor(self, parent, option, index):
         return DateTimeEdit(parent, self.format)
@@ -253,7 +253,7 @@ class CcDateDelegate(QStyledItemDelegate):  # {{{
 
     def setModelData(self, editor, model, index):
         val = editor.dateTime()
-        if val <= UNDEFINED_QDATETIME:
+        if is_date_undefined(val):
             val = None
         model.setData(index, QVariant(val), Qt.EditRole)
 
diff --git a/src/calibre/utils/date.py b/src/calibre/utils/date.py
index 0a8d779af8..dc8adc6b97 100644
--- a/src/calibre/utils/date.py
+++ b/src/calibre/utils/date.py
@@ -75,7 +75,12 @@ def is_date_undefined(qt_or_dt):
     if d is None:
         return True
     if hasattr(d, 'toString'):
-        d = datetime(d.year(), d.month(), d.day(), tzinfo=utc_tz)
+        if hasattr(d, 'date'):
+            d = d.date()
+        try:
+            d = datetime(d.year(), d.month(), d.day(), tzinfo=utc_tz)
+        except ValueError:
+            return True  # Undefined QDate
     return d.year < UNDEFINED_DATE.year or (
             d.year == UNDEFINED_DATE.year and
             d.month == UNDEFINED_DATE.month and