diff --git a/src/calibre/devices/apple/driver.py b/src/calibre/devices/apple/driver.py
index cc4d39d3c5..5a0496e863 100644
--- a/src/calibre/devices/apple/driver.py
+++ b/src/calibre/devices/apple/driver.py
@@ -24,6 +24,7 @@ from calibre.utils.logging import Log
 from calibre.utils.zipfile import ZipFile
 
 from PIL import Image as PILImage
+from lxml import etree
 
 if isosx:
     try:
@@ -2515,23 +2516,23 @@ class ITUNES(DriverBase):
             fnames = zf_opf.namelist()
             opf = [x for x in fnames if '.opf' in x][0]
             if opf:
-                opf_raw = cStringIO.StringIO(zf_opf.read(opf))
-                soup = BeautifulSoup(opf_raw.getvalue())
-                opf_raw.close()
-
-                # Touch existing calibre timestamp
-                md = soup.find('metadata')
-                if md:
-                    ts = md.find('meta',attrs={'name':'calibre:timestamp'})
-                    if ts:
-                        timestamp = ts['content']
-                        old_ts = parse_date(timestamp)
-                        metadata.timestamp = datetime.datetime(old_ts.year, old_ts.month, old_ts.day, old_ts.hour,
-                                                   old_ts.minute, old_ts.second, old_ts.microsecond+1, old_ts.tzinfo)
-                    else:
-                        metadata.timestamp = now()
-                        if DEBUG:
-                            self.log.info("   add timestamp: %s" % metadata.timestamp)
+                opf_tree = etree.fromstring(zf_opf.read(opf))
+                ns_map = opf_tree.nsmap.keys()
+                for item in ns_map:
+                    ns = opf_tree.nsmap[item]
+                    md_el = opf_tree.find(".//{%s}metadata" % ns)
+                    if md_el is not None:
+                        ts = md_el.find('.//{%s}meta[@name="calibre:timestamp"]')
+                        if ts:
+                            timestamp = ts.get('content')
+                            old_ts = parse_date(timestamp)
+                            metadata.timestamp = datetime.datetime(old_ts.year, old_ts.month, old_ts.day, old_ts.hour,
+                                                       old_ts.minute, old_ts.second, old_ts.microsecond+1, old_ts.tzinfo)
+                        else:
+                            metadata.timestamp = now()
+                            if DEBUG:
+                                self.log.info("   add timestamp: %s" % metadata.timestamp)
+                        break
                 else:
                     metadata.timestamp = now()
                     if DEBUG:
@@ -2839,7 +2840,7 @@ class ITUNES(DriverBase):
     def _xform_metadata_via_plugboard(self, book, format):
         ''' Transform book metadata from plugboard templates '''
         if DEBUG:
-            self.log.info("  ITUNES._update_metadata_from_plugboard()")
+            self.log.info("  ITUNES._xform_metadata_via_plugboard()")
 
         if self.plugboard_func:
             pb = self.plugboard_func(self.DEVICE_PLUGBOARD_NAME, format, self.plugboards)
diff --git a/src/calibre/library/catalog.py b/src/calibre/library/catalog.py
index cb55b2318d..f3640af4f0 100644
--- a/src/calibre/library/catalog.py
+++ b/src/calibre/library/catalog.py
@@ -1481,23 +1481,36 @@ class EPUB_MOBI(CatalogPlugin):
             current_author = authors[0]
             for (i,author) in enumerate(authors):
                 if author != current_author and i:
-                    # Exit if author matches previous, but author_sort doesn't match
                     if author[0] == current_author[0]:
-                        error_msg = _('''
-Inconsistent Author Sort values for Author '{0}':
-'{1}' <> '{2}',
-unable to build catalog.\n
-Select all books by '{0}', apply correct Author Sort value in Edit Metadata dialog,
-then rebuild the catalog.\n''').format(author[0],author[1],current_author[1])
-                        self.opts.log.warn('\n*** Metadata error ***')
-                        self.opts.log.warn(error_msg)
+                        if self.opts.fmt == 'mobi':
+                            # Exit if building MOBI
+                            error_msg = _(
+'''Inconsistent Author Sort values for
+Author '{0}':
+'{1}' <> '{2}'
+Unable to build MOBI catalog.\n
+Select all books by '{0}', apply correct Author Sort value in Edit Metadata dialog, then rebuild the catalog.\n''').format(author[0],author[1],current_author[1])
+                            self.opts.log.warn('\n*** Metadata error ***')
+                            self.opts.log.warn(error_msg)
+
+                            self.error.append('Author Sort mismatch')
+                            self.error.append(error_msg)
+                            return False
+                        else:
+                            # Warning if building non-MOBI
+                            if not self.error:
+                                self.error.append('Author Sort mismatch')
+
+                            error_msg = _(
+'''Warning: inconsistent Author Sort values for
+Author '{0}':
+'{1}' <> '{2}'\n''').format(author[0],author[1],current_author[1])
+                            self.opts.log.warn('\n*** Metadata warning ***')
+                            self.opts.log.warn(error_msg)
+                            self.error.append(error_msg)
 
-                        self.error.append('Metadata error')
-                        self.error.append(error_msg)
-                        return False
                     current_author = author
 
-
             self.booksByAuthor = sorted(self.booksByAuthor, key=self.booksByAuthorSorter_author_sort)
 
             # Build the unique_authors set from existing data
@@ -2135,7 +2148,7 @@ then rebuild the catalog.\n''').format(author[0],author[1],current_author[1])
                 if author_count == 1:
                     divOpeningTag.insert(dotc, pBookTag)
                     dotc += 1
-                else:
+                elif divRunningTag:
                     divRunningTag.insert(drtc,pBookTag)
                     drtc += 1