diff --git a/cps/tasks/thumbnail.py b/cps/tasks/thumbnail.py
index 31dc1f7b..00bd09ad 100644
--- a/cps/tasks/thumbnail.py
+++ b/cps/tasks/thumbnail.py
@@ -486,6 +486,9 @@ class TaskClearCoverThumbnailCache(CalibreTask):
     def name(self):
         return 'ThumbnailsClear'
 
+    def __str__(self):
+        return "Delete Thumbnail cache directory"
+
     @property
     def is_cancellable(self):
         return False