"From a usability perspective, error messages are often nightmares. Something has gone wrong with the program and it's up to the user to decide what to do next. Ideally, the program would produce an error message to communicate to the user what went wrong and how to correct the problem. Unfortunately, many error messages fall far short of this goal.
Consider the message in Figure 1, which appeared on my PC shortly after the boot sequence. Imagine the impact this message has on a non-technical user who has no idea what the problem is. The message implies that security has been breached and the situation is desperate. In fact, the situation was not quite so dire; I later identified the error message as coming from my video editor software and everything continued to run just fine. But it's amazing how many design flaws are contained in this message:
1. There is no indication which program produced the error message.
2. The message fails to explain why the program is being terminated.
3. The message is very general. It says "the security information" without any reference to what the information is.
4. The message does not indicate how severe the problem is and whether the user's computer is at risk.
5. The user has no idea how to correct the problem or where to get more help. All he can do is press OK (which it certainly is not)." (Continued via MSDN Magazine, Charles Kreitzberg and Ambrose Little) [Usability Resources]