diff --git a/src/calibre/ebooks/metadata/sources/identify.py b/src/calibre/ebooks/metadata/sources/identify.py
index cd658a0daf..fad810c26e 100644
--- a/src/calibre/ebooks/metadata/sources/identify.py
+++ b/src/calibre/ebooks/metadata/sources/identify.py
@@ -357,11 +357,8 @@ def identify(log, abort, # {{{
             if r.plugin.has_html_comments and r.comments:
                 r.comments = html2text(r.comments)
 
-    dummy = Metadata(_('Unknown'))
     max_tags = msprefs['max_tags']
     for r in results:
-        for f in msprefs['ignore_fields']:
-            setattr(r, f, getattr(dummy, f))
         r.tags = r.tags[:max_tags]
 
     return results
diff --git a/src/calibre/gui2/metadata/single.py b/src/calibre/gui2/metadata/single.py
index 7c9dd00734..4ce76d8cc8 100644
--- a/src/calibre/gui2/metadata/single.py
+++ b/src/calibre/gui2/metadata/single.py
@@ -24,6 +24,7 @@ from calibre.gui2.metadata.basic_widgets import (TitleEdit, AuthorsEdit,
 from calibre.gui2.metadata.single_download import FullFetch
 from calibre.gui2.custom_column_widgets import populate_metadata_page
 from calibre.utils.config import tweaks
+from calibre.ebooks.metadata.book.base import Metadata
 
 class MetadataSingleDialogBase(ResizableDialog):
 
@@ -314,7 +315,11 @@ class MetadataSingleDialogBase(ResizableDialog):
         ret = d.start(title=self.title.current_val, authors=self.authors.current_val,
                 identifiers=self.identifiers.current_val)
         if ret == d.Accepted:
+            from calibre.ebooks.metadata.sources.base import msprefs
             mi = d.book
+            dummy = Metadata(_('Unknown'))
+            for f in msprefs['ignore_fields']:
+                setattr(mi, f, getattr(dummy, f))
             if mi is not None:
                 self.update_from_mi(mi)
             if d.cover_pixmap is not None: