diff --git a/integrations/unstructured/src/haystack_integrations/components/converters/unstructured/converter.py b/integrations/unstructured/src/haystack_integrations/components/converters/unstructured/converter.py
index 1dd339fc9..84143d557 100644
--- a/integrations/unstructured/src/haystack_integrations/components/converters/unstructured/converter.py
+++ b/integrations/unstructured/src/haystack_integrations/components/converters/unstructured/converter.py
@@ -120,8 +120,7 @@ def run(
                 please provide an explicit list of direct paths instead."""
             raise ValueError(error)
 
-        all_filepaths = filepaths.union(filepaths_in_directories)
-
+        all_filepaths = filepaths + filepaths_in_directories
         # currently, the files are converted sequentially to gently handle API failures
         documents = []
         meta_list = normalize_metadata(meta, sources_count=len(all_filepaths))