diff --git a/taskcluster/docker/recipes/ubuntu1804-test-system-setup.sh b/taskcluster/docker/recipes/ubuntu1804-test-system-setup.sh
index 11f96e68240b..541bafbff346 100644
--- a/taskcluster/docker/recipes/ubuntu1804-test-system-setup.sh
+++ b/taskcluster/docker/recipes/ubuntu1804-test-system-setup.sh
@@ -183,3 +183,6 @@ apt-get -y autoremove
 apt-get clean
 apt-get autoclean
 rm -f "$0"
+
+# Pre-create caches for user "worker"
+su --command "fc-cache -vf" worker