The perfect error message


"An error message reading: "Hi, it appears you've previously Signed In to another Optus website using a Optus Mobile Number. Member Services is only available for Optus Internet users. If you are attempting to Sign In with your Optus Internet username, please click on the 'Logout' button in the top right of your screen."

Source: Optus

This error message is perfect because it does *everything* wrong.

An error message should:

  • Explain what happened
  • Explain why it happened
  • Enable you to fix the problem.

This message implies that the user had signed in with a mobile (cellphone) number. I hadn’t. Even if I had, it’s unclear why this should be a problem. The solution offered is to “Logout”.

An organisation should use consistent language. Here, we have “sign in” and “logout” – a clear indication that there is internal dysfunction and disconnection.

A key component of a trusted website is good grammar. Here we have “a Optus Mobile number” instead of “an Optus Mobile number” and “Member Services” treated as singular (“Member Services is only…”). Probably the rationale for the latter is that “Member Services” is an entity of some sort, but it’s clearly a case of the organisation speaking its language rather than that of the user.

The message also has two conflicted personas. The first is the one that opens with “Hi” – it’s the voice that Optus uses in its advertising, and even in its installation guides. When everything is fine, that tone can be acceptable, but when things go pear-shaped, it quickly sounds insincere, flippant or blatantly uncaring.

The internal focus is also apparent in the sentence: “If you are attempting to Sign In with your Optus Internet username…” which assumes that the user knows what an Optus Internet username is. I can only speak from my own experience, and I don’t know what it is (nor do I even have an Optus mobile phone number, so that part of the message is doubly confusing).

In fact, the whole message is so bizarre that the fact that the referenced “Logout” button “in the top right of your screen” does not in fact exist seems only incidental, a mere peccadillo amidst a multitude of other sins.


An online form showing the error "Your captcha result is wrong"

Source: Archilux (a lighting company)

Somebody sent me an email, entitled “WTF,” containing a copy of this error message, which states that “Your captcha result is wrong”.

They had no idea what the message meant. And why should they? “Captcha” is not a word in common usage among non-geeks. And the page, frustratingly, has no other reference to “captcha,” although it does have a mathematical challenge intended to weed out non-humans (and which, arguably among we geeks, is not a “captcha.”)

The problem is compounded by the fact that the field in error is at the bottom of the page, and not visible without scrolling.

The message is also rather hostile in tone. Telling users they have done something “wrong” is so 1970′s!

Error messages should say, in plain language, what happened, why it happened, and how to fix it.

Inhuman time scales

Error message reading" Error 302007: The 'From' date is earlier than 560 days from today's date. Please re-enter another date'"

Source: NAB (an Australian bank)

The most annoying aspect of this message is the reference to the date entered being “earlier than 560 days from today’s date,” which leaves the user with the task of figuring out a date that is less than 560 days in the past.

How hard would it have been to avoid the error by specifying the earliest date adjacent to the field itself? Or to specify the earliest date in the error message? Or to use a human-interpretable date limit like “2 years” (or even “a year and a half”).

The other faults with the message are relatively trivial in comparison:

  • The message begins with “Error 302007,” which is irrelevant to customers.
  • “From today’s date” is less clear than “in the past” (and is arguably ambiguous).
  • The word “re-enter” is less accurate and less clear than “enter”.






A distinct lack of confidence

A message that "We are offering promotional rate for all amendments successfully made online", and with the word "successfully" emphasised.

Source: Regional Express (Rex)

My interpretation is:

“You can try this, but it might not work. If it doesn’t work, you’ll have to call us. And you must acknowledge this message before we can allow you to proceed with attempting this thing that might not work.”

It seems incongruous to flag potential failure. And even odder to force customers to acknowledge the potential for failure before embarking on the transaction in the first place.

In fairness, this message now appears to have been removed. Perhaps the airline has gained greater faith in its IT capability.

It’s the *World* Wide Web

A message that the product is shipping in “Winter 2013/2014″

Source: Tile

While it’s no doubt unintentional, ignoring an entire hemisphere (for which there is no winter in 2013/2014) is easily perceived as being parochial or worse.

Of course, users in the southern hemisphere can fairly readily interpret “Winter 2013/2014″ as meaning sometime around the change of the year. But why should they have to?

That’s OK, then

A Phone Number field with an explanation that "Our shipping providers require a contact phone number"


This form acknowledges that the customer may be reluctant to provide a phone number, and provides an explanation for the requirement.

An assurance that it wouldn’t be used for other purposes might be good, but then the message starts to get rather long. And perhaps it’s adequately implied.

One could argue that having the information displayed by default, instead of requiring a specific action on the part of the customer, would be better.

(Good album, by the way.)