diff --git a/js/models/core/PublicKeyRing.js b/js/models/core/PublicKeyRing.js
index b86f18277..1d0537a09 100644
--- a/js/models/core/PublicKeyRing.js
+++ b/js/models/core/PublicKeyRing.js
@@ -43,9 +43,9 @@ PublicKeyRing.trim = function(data) {
 };
 
 PublicKeyRing.fromObj = function(data) {
-  if (data instanceof PublicKeyRing) {
-    throw new Error('bad data format: Did you use .toObj()?');
-  }
+  preconditions.checkArgument(typeof data !== 'PublicKeyRing');
+
+
   var opts = PublicKeyRing.trim(data);
  
   // Support old indexes schema
diff --git a/test/test.PublicKeyRing.js b/test/test.PublicKeyRing.js
index 4fe8b0f5a..3adfa5231 100644
--- a/test/test.PublicKeyRing.js
+++ b/test/test.PublicKeyRing.js
@@ -434,6 +434,21 @@ describe('PublicKeyRing model', function() {
     w.nicknameForIndex(4).should.equal('juan1');
   });
 
+  it('#fromObj with error', function() {
+
+    var config = {
+      networkName: 'livenet',
+    };
+    var pkr = new PublicKeyRing(config);
+
+
+    (function () 
+    {
+      PublicKeyRing.fromObj(pkr);
+    }
+    ).should.throw('bad data format: Did you use .toObj()?');  
+  });
+
 
   it('#toObj #fromObj with nickname', function() {
     var config = {