Tina

Would you rather have a way to "find" an existing number if one existed, or
have your computer tell you that you can't use the number you just tried to
use?

It might be a bit more user friendly to provide a combobox (drop-down)
containing existing [ShipmentNumber]s, set the LimitToList property to Yes,
and add a NotInList event to allow the user to create a new
[ShipmentNumber]. More work for you, (much) less for the user...

Good luck!

Regards

Jeff Boyce
Microsoft Access MVP

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"Tina" wrote in message
...
How can I display a message box on a form if the shipment number is a
duplicate? I need a message box to pop up when user attempts to tab out
of
the field.

Thank you.