If for some reason your user has no published fields, make sure Meteor.user()

still returns a (trivial) object.

packages/accounts-base/accounts_client.js

@@ -17,9 +17,13 @@
     var userId = Meteor.userId();
     if (!userId)
       return null;
-    if (Meteor.userLoaded())
-      return Meteor.users.findOne(userId);
-    // Not yet loaded: return a minimal object.
+    if (Meteor.userLoaded()) {
+      var user = Meteor.users.findOne(userId);
+      if (user) return user;
+    }
+    // Either the subscription isn't done yet, or for some reason this user has
+    // no published fields (and thus is considered to not exist in
+    // minimongo). Return a minimal object.
     return {_id: userId};
   };