You or your system may issue error messages, but it's important to keep in mind how they're received. Taking this into account can help smooth transactions on both ends, eliminating confusion and further calls from customers for assistance. Consider these real-life examples of clumsy error messages I've received lately.
Incident 1: I recently received a credit card, and with it instructions on activating it via a toll-free telephone number. I called the number, and when the system answered, it asked me to enter the telephone number associated with my application. I entered my office number, but then heard the system tell me it didn't match the number it had on file. "No problem," I thought, "I think I used my home number." Well, I put that number in, and received the same response. I entered my cell phone number and received still the same result. Annoyed by this time, I called their customer support line. The representative checked the system, and told me they had NO telephone number on file for me. She proceeded to activate the card for me, and I was all set.
Incident 2: I had booked an online reservation on US Airways a few weeks prior to the scheduled flight. Shortly before that time, I signed on to check in and print my boarding pass. However, when I entered my confirmation number, I received a message saying that my reservation record, which I entered correctly, could not be found. After a few seconds, during which my heart resumed beating, I read the fine print, which I had missed before. It made me realize that I had tried to check in outside the allowable window for doing so (at that time, 12 hours prior to departure). I waited until I was within that window, entered the same confirmation number and successfully checked in.
In both cases, an application program caught and flagged an error associated with an action I had taken. However, in both cases, the resulting message proved unhelpful. In one case, it caused me to waste time, and in the other, it almost gave me a heart attack.
How could these messages be made more meaningful? What if, in the first case, the message said, "We have no telephone number on file for this card. Please press 0 to speak to a representative"? What if, in the second case, the message told me that I needed to wait until I was within 12 hours of departure?
At this point, you might be questioning the credit card example, asking yourself how the application could have been accepted with a telephone number. It sounds like the editing process for the application had a deficiency. Therefore, maybe it's not fair to blame the software program that does the activation, because the software program that accepted the card application failed to do its job. Regardless, though, the error message did cause me to waste time.
Think about your user when you develop your error messages. Try to make the message as specific as possible to the error. More importantly, phrase the message so that it tells the user how to resolve the error. When your error messages prove meaningful, your customers will be able to resolve more problems themselves and thus spend less time calling you.