diff --git a/src/calibre/gui2/tweak_book/file_list.py b/src/calibre/gui2/tweak_book/file_list.py
index dc533307ff..f8acacbe85 100644
--- a/src/calibre/gui2/tweak_book/file_list.py
+++ b/src/calibre/gui2/tweak_book/file_list.py
@@ -128,7 +128,7 @@ class FileList(QTreeWidget):
             emblems = []
             if name in {cover_page_name, cover_image_name}:
                 emblems.append('default_cover.png')
-            if name not in manifested_names and name not in {container.opf_name, 'META_INF/container.xml', 'META_INF/encryption.xml'}:
+            if name not in manifested_names and name not in {container.opf_name, 'META-INF/container.xml', 'META-INF/encryption.xml'}:
                 emblems.append('dialog_question.png')
             if not linear:
                 emblems.append('arrow-down.png')