In case of unhandled code exceptions, what is the most appropriate thing to show the end user?

Question

In a web application, when your server side code screws up and experiences an unhandled exception, what is the most appropriate way to tell the end users of what happened? Do you simply say "Something unexpected happened and we are sorry". Should you try to make some sense of what the exception was and what the user was trying to do and let them know how to recover, if at all thats possible?

Answer 1

The Lynx text-based browser has a nice message, something like: Congratulations, you have found a bug in Lynx! Following are instructions for filing a bug report (mainly sending a log file to a given email).

Answer 2

End users will care a great deal if they are part way through a transaction when this happens and they have to start again. As far as possible you should try and maintain their client state (i.e. form values they have typed in). That's probably your most important consideration if you are looking to keep them happy.

Most end users will not appreciate a witty remark about how lucky they are to have found your bug, in fact it is more likely to greatly annoy them. If you want to use your users to report bugs (and they will do it) then show them an error code and short description and get them to pass it back to you in its entirety.

In all cases you need to try as far as possible to give them a clear instruction on what to do next e.g. "There has been an unexpected error. Press send again" Best guidance is to keep the language formal and concise, you don't need lots of please and thank you, although it may suit your polite nature. You want messages to be short, concise and didactic rather than chatty.