diff --git a/tools/Dockerfile.tail b/tools/Dockerfile.tail
index 5a6a66c25..521414df5 100644
--- a/tools/Dockerfile.tail
+++ b/tools/Dockerfile.tail
@@ -1,5 +1,5 @@
 RUN <<EOF
-find ${prefix} -type f \
+find "${prefix}" -type f \
 | grep -v "${prefix}${docker_setup_manifests}/${name}.txt" \
 >"${prefix}${docker_setup_manifests}/${name}.txt"
 EOF