diff --git a/lightrag/lightrag.py b/lightrag/lightrag.py
index 1f61a42e..69ef8811 100644
--- a/lightrag/lightrag.py
+++ b/lightrag/lightrag.py
@@ -900,9 +900,15 @@ class LightRAG:
                 # Get first document's file path and total count for job name
                 first_doc_id, first_doc = next(iter(to_process_docs.items()))
                 first_doc_path = first_doc.file_path
-                path_prefix = first_doc_path[:20] + (
-                    "..." if len(first_doc_path) > 20 else ""
-                )
+
+                # Handle cases where first_doc_path is None
+                if first_doc_path:
+                    path_prefix = first_doc_path[:20] + (
+                        "..." if len(first_doc_path) > 20 else ""
+                    )
+                else:
+                    path_prefix = "unknown_source"
+
                 total_files = len(to_process_docs)
                 job_name = f"{path_prefix}[{total_files} files]"
                 pipeline_status["job_name"] = job_name