diff --git a/src/calibre/ebooks/metadata/sources/identify.py b/src/calibre/ebooks/metadata/sources/identify.py
index 6295efa0c0..4d21a0c210 100644
--- a/src/calibre/ebooks/metadata/sources/identify.py
+++ b/src/calibre/ebooks/metadata/sources/identify.py
@@ -382,7 +382,11 @@ def identify(log, abort, # {{{
             log(plog)
         log('\n'+'*'*80)
 
+        dummy = Metadata(_('Unknown'))
         for i, result in enumerate(presults):
+            for f in plugin.prefs['ignore_fields']:
+                if ':' not in f:
+                    setattr(result, f, getattr(dummy, f))
             result.relevance_in_source = i
             result.has_cached_cover_url = (plugin.cached_cover_url_is_reliable
                     and plugin.get_cached_cover_url(result.identifiers) is not
diff --git a/src/calibre/ebooks/metadata/sources/overdrive.py b/src/calibre/ebooks/metadata/sources/overdrive.py
index 26c25b627f..0affbdd805 100755
--- a/src/calibre/ebooks/metadata/sources/overdrive.py
+++ b/src/calibre/ebooks/metadata/sources/overdrive.py
@@ -41,10 +41,6 @@ class OverDrive(Source):
     supports_gzip_transfer_encoding = False
     cached_cover_url_is_reliable = True
 
-    def __init__(self, *args, **kwargs):
-       Source.__init__(self, *args, **kwargs)
-       self.prefs.defaults['ignore_fields'] =['tags', 'pubdate', 'comments']
-
     def identify(self, log, result_queue, abort, title=None, authors=None, # {{{
             identifiers={}, timeout=30):
         ovrdrv_id = identifiers.get('overdrive', None)
@@ -390,7 +386,10 @@ class OverDrive(Source):
 
         if pub_date:
             from calibre.utils.date import parse_date
-            mi.pubdate = parse_date(pub_date[0].strip())
+            try:
+                mi.pubdate = parse_date(pub_date[0].strip())
+            except:
+                pass
         if lang:
             lang = lang[0].strip().lower()
             mi.language = {'english':'en', 'french':'fr', 'german':'de',