Use a Date/Time field and they'll have no choice in the matter. Otherwise you're going to be limited to forcing them to use one format, or using IsDate() as a check before processing.
I appreciate your response but I do not believe it is correct. The field is date/time. If you enter just a date, the time is defaulted to 12:00 AM. I did find a solution:
format mm/dd/yy hh:nn AM/PM
input mask - 00/00/00\ 00:00\ >LL;0;" "
Sorry, I misunderstood what you meant by "require them to enter date and time". Glad you got it working.
You could probably also do a validation check that made sure the time component wasn't 0.
Code:
Private Sub DateTimeField_BeforeUpdate(Cancel As Integer)
Dim m As Integer
If Int(Me.DateTimeField.Value) = Me.DateTimeField.Value Then
m = MsgBox("Is the time for this entry truly 12:00 AM?",vbYesNo)
If m = vbNo Then
Me.Undo
Cancel = True
End If
End If
End Sub