So what makes a good error message then? To me, it boils down to three pieces of information which should be conveyed by an error message: Context: What led to the error? What was the code trying to do when it failed? The error itself: What exactly failed? Mitigation: What needs to be done in order to overcome the error?

The ideal goal is to not need to use error messages at all. Look instead to design what Don Norman calls a ‘collaborative’ system, tell the user the requirements before they do the work.

Where Error Messages are used try to ensure they sound like they’ve been written for real people to understand

Think of the error message as a conversation with the person using the system. Make it polite, understandable, friendly & jargon-free. The goal is to write an actionable error message that anyone could understand.

If you’re a writer, designer, or developer working on an app, you can help reduce your users’ frustration by being more thoughtful about the errors you display.

Of course, the best error message is no error message at all. In the case where something has gone awry, a program should do everything within its power to remedy the situation at hand.

A well-constructed error message should identify the program that is posting the error message should alert the customer to the specific problem should provide some specific indication as to how the problem may be solved should suggest where the customer may obtain further help should provide extra information to the person who is helping the customer should not suggest an action that will fail to solve the problem and thus waste the customer's time should not contain information that is unhelpful, redundant, incomplete, or inaccurate should provide an identifying code to distinguish it from other, similar messages

When you're constructing an error message, the important thing to remember is that your message must convey useful information.

Due to color vision deficiencies, it’s a good idea to always complement error messages with an icon