diff --git a/src/calibre/gui2/main_window.py b/src/calibre/gui2/main_window.py
index 0a02091482..e6e8e8798a 100644
--- a/src/calibre/gui2/main_window.py
+++ b/src/calibre/gui2/main_window.py
@@ -203,8 +203,10 @@ class MainWindow(QMainWindow):
 
         path_map = {x['path']: x for x in p}
         is_folder = fname and os.path.isdir(fname)
-        w = _('folder') if is_folder else _('file')
-        dmsg = _('Could not open the {0}: "{1}". It is already opened in the following programs:').format(w, fname) + '<div>'
+        if is_folder:
+            dmsg = _('Could not open the folder: "{}". It is already opened in the following programs:').format(fname)
+        else:
+            dmsg = _('Could not open the file: "{}". It is already opened in the following programs:').format(fname)
         for path, x in path_map.items():
             dmsg += '<div>' + prepare_string_for_xml(f'{x["app_name"]}: {path}')
         msg = prepare_string_for_xml(msg)