diff --git a/lib/lxc_collector.rb b/lib/lxc_collector.rb
index e8dac70..c7c374b 100755
--- a/lib/lxc_collector.rb
+++ b/lib/lxc_collector.rb
@@ -98,7 +98,7 @@ class LxcCollector
               end
             wr.write [:pkgs, {
               id: ct.name, name: name, upgradable: upgradable,
-              last_update: AptLastUpdateFile.stat.mtime.to_f,
+              last_update: AptLastUpdateFile.exist? ? AptLastUpdateFile.stat.mtime.to_f : -1,
             }]
           end
         end