diff --git a/src/calibre/ebooks/metadata/sources/overdrive.py b/src/calibre/ebooks/metadata/sources/overdrive.py
index 5f70802314..26c25b627f 100755
--- a/src/calibre/ebooks/metadata/sources/overdrive.py
+++ b/src/calibre/ebooks/metadata/sources/overdrive.py
@@ -43,7 +43,7 @@ class OverDrive(Source):
 
     def __init__(self, *args, **kwargs):
        Source.__init__(self, *args, **kwargs)
-       self.prefs.defaults['ignore_fields'] =['tags', 'pubdate', 'comments', 'identifier:isbn']
+       self.prefs.defaults['ignore_fields'] =['tags', 'pubdate', 'comments']
 
     def identify(self, log, result_queue, abort, title=None, authors=None, # {{{
             identifiers={}, timeout=30):
diff --git a/src/calibre/gui2/metadata/bulk_download2.py b/src/calibre/gui2/metadata/bulk_download2.py
index 4aa4561078..2bbb177e14 100644
--- a/src/calibre/gui2/metadata/bulk_download2.py
+++ b/src/calibre/gui2/metadata/bulk_download2.py
@@ -310,7 +310,8 @@ def proceed(gui, job):
 def merge_result(oldmi, newmi):
     dummy = Metadata(_('Unknown'))
     for f in msprefs['ignore_fields']:
-        setattr(newmi, f, getattr(dummy, f))
+        if ':' not in f:
+            setattr(newmi, f, getattr(dummy, f))
     fields = set()
     for plugin in metadata_plugins(['identify']):
         fields |= plugin.touched_fields
diff --git a/src/calibre/gui2/metadata/single.py b/src/calibre/gui2/metadata/single.py
index d527dda022..63d4499966 100644
--- a/src/calibre/gui2/metadata/single.py
+++ b/src/calibre/gui2/metadata/single.py
@@ -326,7 +326,8 @@ class MetadataSingleDialogBase(ResizableDialog):
             mi = d.book
             dummy = Metadata(_('Unknown'))
             for f in msprefs['ignore_fields']:
-                setattr(mi, f, getattr(dummy, f))
+                if ':' not in f:
+                    setattr(mi, f, getattr(dummy, f))
             if mi is not None:
                 self.update_from_mi(mi)
             if d.cover_pixmap is not None: