diff --git a/inc/myco_objects.js b/inc/myco_objects.js
index 626f5a1..e97910c 100644
--- a/inc/myco_objects.js
+++ b/inc/myco_objects.js
@@ -3,11 +3,26 @@ function GroupList() {
   lastChange=0;
   
   this.loadFromLocalStorage=function() {
-    if (localStorage.groups!==undefined) {
-      var data=JSON.parse(localStorage.groups);
-      this.lastChange=data.lastChange;
-      for (el in data.groups) {
-        this[el]=new Group(el,data.groups[el]);
+    if (jQuery.type(localStorage.groups)!='undefined') {
+      try {
+        var data=JSON.parse(localStorage.groups);
+        this.lastChange=data.lastChange;
+        for (el in data.groups) {
+          this[el]=new Group(el,data.groups[el]);
+        }
+      }
+      catch(e) {
+        for (el in this) {
+          if (this.isGroup(this[el])) {
+            delete this[el];
+          }
+        }
+        myconfirm('Erreur en chargeant les données locales. On les purges ?',
+          function(data) {
+            delete localStorage.groups;
+            location.reload();
+          }
+        );
       }
     }
   }