diff --git a/images/base/Dockerfile b/images/base/Dockerfile
index 0e658db..2bbccde 100644
--- a/images/base/Dockerfile
+++ b/images/base/Dockerfile
@@ -24,7 +24,8 @@ RUN apt-get update \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*
 
-RUN groupadd --gid $USER_GID $USERNAME \
+RUN userdel -r ubuntu 2>/dev/null; groupdel ubuntu 2>/dev/null; \
+    groupadd --gid $USER_GID $USERNAME \
     && useradd -s /bin/bash --uid $USER_UID --gid $USER_GID -m $USERNAME \
     && echo "$USERNAME ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/$USERNAME \
     && chmod 0440 /etc/sudoers.d/$USERNAME