diff --git a/images/imap-download/Dockerfile b/images/imap-download/Dockerfile
index 9e8c90c..c215a1a 100644
--- a/images/imap-download/Dockerfile
+++ b/images/imap-download/Dockerfile
@@ -7,7 +7,7 @@ RUN install_packages ca-certificates fetchmail procmail inotify-tools mpack
 RUN mkdir /srv/home \
 	&& ln -s /mnt/fetchmailrc /srv/home/.fetchmailrc \
 	&& mkdir /tmp/maildir \
-	&& groupmod -g 10000 fetchmail \
+	&& groupadd --gid 10000 fetchmail \
 	&& usermod --uid 10000 --gid 10000 --home=/srv/home --uid=10000 --gi=10000 fetchmail \
 	&& chown fetchmail:fetchmail /srv/home