diff --git a/guacamole/Dockerfile b/guacamole/Dockerfile
index 09b16d14f..1f21cd87b 100644
--- a/guacamole/Dockerfile
+++ b/guacamole/Dockerfile
@@ -57,7 +57,10 @@ RUN \
     && sed -i '\|<dir>/usr/share/fonts</dir>|a\ \ \ \ \ \ \ \ <dir>/config/fonts</dir>' /etc/fonts/fonts.conf \
     \
     # Avoid https://github.com/alexbelgium/hassio-addons/issues/659
-    && rm -r /run/shm
+    && rm -r /run/shm \
+    \
+    # Avoid variable unset
+    && sed -i '1a set +u' /etc/services.d/guacamole/run
 
 ##################
 # 3 Install apps #