...

src/calibre/library/database2.py

@@ -443,6 +443,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
                 self.add_format(id, format, stream, index_is_id=True,
                         path=tpath, notify=False)
         self.conn.execute('UPDATE books SET path=? WHERE id=?', (path, id))
+        self.conn.commit()
         self.data.set(id, self.FIELD_MAP['path'], path, row_is_id=True)
         # Delete not needed directories
         if current_path and os.path.exists(spath):

src/calibre/utils/ipc/server.py

@@ -195,8 +195,7 @@ class Server(Thread):
                         job.result = cPickle.load(open(worker.rfile, 'rb'))
                         os.remove(worker.rfile)
                     except:
-                        import traceback
-                        traceback.print_exc()
+                        pass
                 job.duration = time.time() - job.start_time
                 self.changed_jobs_queue.put(job)