How to Design Error Messages

I haven’t written about one of my favorite services for several moths already, but as usual Pandora gave me a reason to post a comment. When I was trying to “thumb up” a song an error occurred. It wasn’t a typical error message however:


First, it’s written clearly and in human language. It’s as clear as a day which action failed. Second, I’m really touched when the application apologizes: “I’m sorry. It’s my fault.” So nice. Well written error message can really make the difference and even make the user feel better.

There are a couple of things more. The message window looks nice. Font is big and easily readable. There is no OK button, because it’s far from OK when I can’t use one of basic features. The retry option (the positive one) is more exposed than the cancel option (the negative one).

On the other hand you can find error messages like that:


It’s ugly and clumsy. It forces you to agree that it’s OK that the error has appeared. And for most of users it’s completely incomprehensible. On the contrary to Pandora's message that's the great example how error messages shouldn’t be made. Alas, not so rare example.