diff --git a/neo/io/__init__.py b/neo/io/__init__.py
index 22b6df662..59d07bb09 100644
--- a/neo/io/__init__.py
+++ b/neo/io/__init__.py
@@ -429,7 +429,7 @@ def list_candidate_ios(file_or_folder, ignore_patterns=['*.ini', 'README.txt', '
     """
     file_or_folder = pathlib.Path(file_or_folder)
 
-    if file_or_folder.is_file():
+    if file_or_folder.suffix:
         suffix = file_or_folder.suffix[1:].lower()
         if suffix not in io_by_extension:
             raise ValueError(f'{suffix} is not a supported format of any IO.')