diff --git a/src/calibre/devices/usbms/driver.py b/src/calibre/devices/usbms/driver.py
index dc0299b46e..b86d61182d 100644
--- a/src/calibre/devices/usbms/driver.py
+++ b/src/calibre/devices/usbms/driver.py
@@ -382,7 +382,8 @@ class USBMS(CLI, Device):
             os.makedirs(self.normalize_path(self._main_prefix))
 
         def write_prefix(prefix, listid):
-            if prefix is not None and isinstance(booklists[listid], self.booklist_class):
+            if (prefix is not None and len(booklists) > listid and
+                    isinstance(booklists[listid], self.booklist_class)):
                 if not os.path.exists(prefix):
                     os.makedirs(self.normalize_path(prefix))
                 with open(self.normalize_path(os.path.join(prefix, self.METADATA_CACHE)), 'wb') as f: