diff --git a/Dockerfile b/Dockerfile
index a3b62b0..2d592ad 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -14,7 +14,7 @@ RUN apt-get update ;\
 
 RUN mkdir /.seafile; mkdir /volume; touch supervisord.log
 
-ARG UNAME=seafuser
+ENV UNAME=seafuser
 ENV UID=1000
 ENV GID=1000
 RUN groupadd -g $GID -o $UNAME ;\