diff --git a/penta-sessions.js b/penta-sessions.js
index d8765de98b7c3920b997fe873736431e5013b651..be9d2f26d0c3dccdfa85907306f666532e2f487b 100644
--- a/penta-sessions.js
+++ b/penta-sessions.js
@@ -72,7 +72,7 @@ group.commands.add(['sessions[ave]','mkses[sion]'],
     'Save current window',
     function(args) {
         let filename = args[0] ? (/^~?\//.test(args[0]) ? args[0] :
-                options.sessiondir+args[0]) : options.sessiondir+Date.now()+'.penta'
+                options.sessiondir+args[0]) : options.sessiondir+new Date().toLocaleString().replace(/\s/g,"_")+'.penta'
         let file = io.File(filename);
       
         dactyl.assert(!file.exists() || args.bang, _("io.exists", file.path.quote()));