diff --git a/app/models/comment.rb b/app/models/comment.rb
index 40d69240..c699f18a 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -41,7 +41,11 @@ class Comment < ActiveRecord::Base
   }
 
   scope :find_since_last_login, lambda { |user|
-    where(created_at: (user.last_sign_in_at..Time.now)).order(created_at: :desc)
+    if user.last_sign_in_at
+      where(created_at: (user.last_sign_in_at..Time.now)).order(created_at: :desc)
+    else
+      none
+    end
   }
   # Helper class method to look up a commentable object
   # given the commentable class name and id
diff --git a/app/models/user.rb b/app/models/user.rb
index 4ca0418f..5a14e885 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -74,7 +74,9 @@ class User < ActiveRecord::Base
     raise UserDisabled if user && user.is_disabled
 
     if user
-      user.update_attributes(email: attributes[:email])
+      user.update_attributes(email: attributes[:email],
+                             last_sign_in_at: user.current_sign_in_at,
+                             current_sign_in_at: Time.current)
     else
       begin
         user = create!(username: username, email: attributes[:email])
diff --git a/spec/models/comment_spec.rb b/spec/models/comment_spec.rb
new file mode 100644
index 00000000..94cb6372
--- /dev/null
+++ b/spec/models/comment_spec.rb
@@ -0,0 +1,10 @@
+require 'spec_helper'
+
+describe Commercial do
+
+  describe '.find_since_last_login' do
+    it 'returns none if last_sign_in_at is nil' do
+      expect(Comment.find_since_last_login(create(:user))).to eq(Comment.none)
+    end
+  end
+end