diff --git a/scripts/tag_autocomplete_helper.py b/scripts/tag_autocomplete_helper.py
index 3a4cefb..f2d8d79 100644
--- a/scripts/tag_autocomplete_helper.py
+++ b/scripts/tag_autocomplete_helper.py
@@ -683,7 +683,7 @@ def api_tac(_: gr.Blocks, app: FastAPI):
         global last_style_mtime
         
         mtime = get_style_mtime()
-        if mtime > last_style_mtime:
+        if mtime is not None and mtime > last_style_mtime:
             last_style_mtime = mtime
             # Update temp file
             if shared.prompt_styles is not None: