diff --git a/backend/open_webui/tools/builtin.py b/backend/open_webui/tools/builtin.py
index 853aaaa9d5..ed6ad9d4a6 100644
--- a/backend/open_webui/tools/builtin.py
+++ b/backend/open_webui/tools/builtin.py
@@ -2489,7 +2489,7 @@ async def grep_chat_files(
         if not files_to_search:
             return JSONCodec.dumps({'error': 'No accessible files found'})
 
-        return _grep_file_models(files_to_search, pattern, case_insensitive, count_only)
+        return await asyncio.to_thread(_grep_file_models, files_to_search, pattern, case_insensitive, count_only)
     except Exception as e:
         log.exception(f'grep_chat_files error: {e}')
         return JSONCodec.dumps({'error': str(e)})
@@ -2727,7 +2727,7 @@ async def grep_knowledge_files(
         if not files_to_search:
             return JSONCodec.dumps({'error': 'No accessible files found'})
 
-        return _grep_file_models(files_to_search, pattern, case_insensitive, count_only)
+        return await asyncio.to_thread(_grep_file_models, files_to_search, pattern, case_insensitive, count_only)
 
     except Exception as e:
         log.exception(f'grep_knowledge_files error: {e}')