It is listed by many here as a solution for trapping an invalid date and displaying your own message. If you have a textbox formatted as a date, such as by setting the value to Date(), you can not trap the "invalid date..." wait window.

If you search for "readerror..." here you will see what I'm talking about.

>>I am trying to make use of the method described in other messages here of using "On Readerror..." to try and trap date entry errors. I've tried placing the statement in the gotfocus and the when events of the date control. This control is the fifth control on the form.
>>
>>However, if one of the first controls on the form returns false from "valid", it's firing the "On readerror..." statement in the date control.
>>
>>What am I missing?
>
>Why you use it?
>HELP said: Included for backward compatibility. Use the Valid event instead.
>Why you just not validate whole entry at once in some method and then allow to user to write the record?