diff --git a/manifests/install/windows.pp b/manifests/install/windows.pp
index 5da7328e..f3e5b24c 100644
--- a/manifests/install/windows.pp
+++ b/manifests/install/windows.pp
@@ -57,7 +57,7 @@
     $_puppet_run_wait = undef
   }
 
-  $_timestamp = strftime('%Y_%m_%d-%H_%M')
+  $_timestamp = Timestamp().strftime('%Y_%m_%d-%H_%M')
   $_logfile = windows_native_path("${facts['env_temp_variable']}/puppet-${_timestamp}-installer.log")
 
   notice ("Puppet upgrade log file at ${_logfile}")