diff --git a/intel_extension_for_transformers/neural_chat/pipeline/plugins/retrieval/requirements.txt b/intel_extension_for_transformers/neural_chat/pipeline/plugins/retrieval/requirements.txt
index d6476230563..617ce46b8d7 100644
--- a/intel_extension_for_transformers/neural_chat/pipeline/plugins/retrieval/requirements.txt
+++ b/intel_extension_for_transformers/neural_chat/pipeline/plugins/retrieval/requirements.txt
@@ -9,6 +9,7 @@ langchain_core==0.1.35
 langid
 markdown
 openpyxl
+protobuf==3.20
 PyMuPDF
 python-docx
 qdrant-client==1.9.0