diff --git a/stackinator/templates/spack.yaml b/stackinator/templates/spack.yaml
index 65775f90..0faf390a 100644
--- a/stackinator/templates/spack.yaml
+++ b/stackinator/templates/spack.yaml
@@ -105,7 +105,6 @@ spack:
   # ---- Internal tools group ----
   # squashfs is required to create the final squashfs image.
   - group: uenv_tools
-    explicit: false
 {% if not system_gcc %}
     needs: [gcc]
 {% endif %}