diff --git a/Dockerfile b/Dockerfile
index 7b6f7ee..9d0913b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,8 @@ ARG NB_GID="100"
 FROM ${LAB_IMAGE}
 
 USER root
-RUN apt-get install --yes --no-install-recommends \
+RUN apt-get update --yes && \
+    apt-get install --yes --no-install-recommends \
     git-lfs 
 USER ${NB_UID}
 RUN echo "install custom extensions"