diff --git a/grouper-appliance.json b/grouper-appliance.json
index c341456..f6de934 100644
--- a/grouper-appliance.json
+++ b/grouper-appliance.json
@@ -93,14 +93,14 @@
   "post-processors": [
     {
       "type": "compress",
-      "format": "tar.gz",
+      "format": ".tar.gz",
       "only": ["grouper-appliance-centos7"],
       "compression_level": "9",
       "output": "builds/TIER-{{user `outputfile_name`}}-ova-{{user `timestamper`}}.tar.gz"
     },
     {
       "type": "compress",
-      "format": "tar.gz",
+      "format": ".tar.gz",
       "only": ["grouper-appliance-centos7-vmware"],
       "compression_level": "9",
       "output": "builds/TIER-{{user `outputfile_name`}}-vmware-{{user `timestamper`}}.tar.gz"