diff --git a/main/src/com/google/refine/io/FileProjectManager.java b/main/src/com/google/refine/io/FileProjectManager.java
index beccf4c5a..e56c0f97f 100644
--- a/main/src/com/google/refine/io/FileProjectManager.java
+++ b/main/src/com/google/refine/io/FileProjectManager.java
@@ -430,6 +430,11 @@ public class FileProjectManager extends ProjectManager {
             try {
                 boolean found = false;
                 JSONObject placeHolderJsonObj = userMetadataPreference.getJSONObject(index);
+                
+                if (!isValidUserMetaDataDefinition(placeHolderJsonObj)) {
+                    logger.warn("Skipped invalid user metadata definition" + placeHolderJsonObj.toString());
+                    continue;
+                }
 
                 for (int i = 0; i < jsonObjArray.length(); i++) {
                     JSONObject jsonObj = jsonObjArray.getJSONObject(i);
@@ -452,6 +457,17 @@ public class FileProjectManager extends ProjectManager {
             }
         }
     }
+    
+    /**
+     * A valid user meta data definition should have name and display property
+     * @param placeHolderJsonObj
+     * @return
+     */
+    private boolean isValidUserMetaDataDefinition(JSONObject placeHolderJsonObj) {
+        return (placeHolderJsonObj != null &&
+                placeHolderJsonObj.has("name") &&
+            placeHolderJsonObj.has("display"));
+    }
 
     protected void recover() {
         boolean recovered = false;
diff --git a/main/webapp/modules/core/scripts/index/open-project-ui.js b/main/webapp/modules/core/scripts/index/open-project-ui.js
index 8bb616bdc..c14a3a313 100644
--- a/main/webapp/modules/core/scripts/index/open-project-ui.js
+++ b/main/webapp/modules/core/scripts/index/open-project-ui.js
@@ -264,11 +264,21 @@ Refine.OpenProjectUI.prototype._renderProjects = function(data) {
       renderProject(projects[i]);
     }
     
+    $.tablesorter.addParser({
+        id: "isoDateParser",
+        is: function(s) {
+            return (/^\d{4}[\/\-]\d{1,2}[\/\-]\d{1,2}T\d{2}:\d{2}:\d{2}[\+,\-\.]\d{3}/).test(s);
+        },
+        format: function(s, table) {
+            return $.tablesorter.formatFloat((s !== "") ? (new Date(s).getTime() || "") : "", table);
+        },
+        type: "numeric"
+    });
 
     $(table).tablesorter({
         headers : {
             3 : {
-                sorter : "time"
+                sorter : "isoDateParser"
             }
         }
     });