diff --git a/src/calibre/customize/profiles.py b/src/calibre/customize/profiles.py
index 18a80cb33d..63c189d712 100644
--- a/src/calibre/customize/profiles.py
+++ b/src/calibre/customize/profiles.py
@@ -363,7 +363,7 @@ class NookOutput(OutputProfile):
     description = _('This profile is intended for the B&N Nook.')
 
     # Screen size is a best guess
-    screen_size               = (600, 770)
+    screen_size               = (600, 730)
     dpi                       = 167
     fbase                     = 16
     fsizes                    = [12, 12, 14, 16, 18, 20, 22, 24]
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index 94b77d17f3..6058212b38 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -24,6 +24,7 @@ class DuplicatesAdder(QThread):
     def run(self):
         count = 1
         for mi, cover, formats in self.duplicates:
+            formats = [f for f in formats if not f.lower().endswith('.opf')]
             id = self.db.create_book_entry(mi, cover=cover,
                     add_duplicates=True)
             self.db_adder.add_formats(id, formats)
@@ -139,6 +140,7 @@ class DBAdder(Thread):
             if id is None:
                 self.duplicates.append((mi, cover, formats))
             else:
+                formats = [f for f in formats if not f.lower().endswith('.opf')]
                 self.add_formats(id, formats)
         else:
             self.names.append(name)