diff --git a/cps/editbooks.py b/cps/editbooks.py
index dd8bf420..17a01b4f 100644
--- a/cps/editbooks.py
+++ b/cps/editbooks.py
@@ -1018,7 +1018,7 @@ def upload():
                                                    config.config_calibre_dir,
                                                    input_authors[0],
                                                    meta.file_path,
-                                                   title_dir + meta.extension)
+                                                   title_dir + meta.extension.lower())
 
                 move_coverfile(meta, db_book)