diff --git a/src/calibre/gui2/library/models.py b/src/calibre/gui2/library/models.py
index a2555cfc56..ef251a884a 100644
--- a/src/calibre/gui2/library/models.py
+++ b/src/calibre/gui2/library/models.py
@@ -156,6 +156,8 @@ class BooksModel(QAbstractTableModel): # {{{
             self.cover_cache.stop()
         self.cover_cache = CoverCache(db, FunctionDispatcher(self.db.cover))
         self.cover_cache.start()
+        if self.metadata_backup is not None:
+            self.metadata_backup.stop()
         self.metadata_backup = MetadataBackup(db)
         self.metadata_backup.start()
         def refresh_cover(event, ids):
diff --git a/src/calibre/library/caches.py b/src/calibre/library/caches.py
index bc16681f81..8d449974a5 100644
--- a/src/calibre/library/caches.py
+++ b/src/calibre/library/caches.py
@@ -43,7 +43,7 @@ class MetadataBackup(Thread): # {{{
     def run(self):
         while self.keep_running:
             try:
-                id_ = self.db.dirtied_queue.get()
+                id_ = self.db.dirtied_queue.get(True, 2)
             except Empty:
                 continue
             except:
@@ -122,7 +122,7 @@ class CoverCache(Thread): # {{{
     def run(self):
         while self.keep_running:
             try:
-                id_ = self.load_queue.get()
+                id_ = self.load_queue.get(True, 2)
             except Empty:
                 continue
             except: