Hi June7
Yes it does. Basically it means that Access doesn't like it if your not in the US!.
I understand what the problem is, but I don't know how to go about resolving it.
Seriously though, it got me thinking that maybe I've been trying to be too clever, and don't really need to test for the Service Date all.
All I really need to do is search the xServices table for the last entry for a customer for their machine number as defined on the Machine Components form. If there is a value in the Follow Up Required field then display the text box, otherwise don't display the text box. It should work in cases where customers have more than one machine as well.
So I think If I remove the date criteria from the statement, this will give me the result that I want. What do you think? Something like this.
=DLookUp("[Follow Up Required]","xServices","[Machine No]='" & [MachineNo] & "' AND DMax("[Machine No]","xServices","[Machine No]='" & [MachineNo] & "'") & "#")