You mean you get a totally blank form, or at least a blank Detail
section?  That happens when there are no existing records to display,
and no records can be added for some reason.  Reasons for that could be
(a) the form's AllowAdditions property is set to No, or (b) the form's
recordsource is not updatable.  If the problem is (b), then the most
common cause is that the recordsource is a query that is not updatable.
This can happen for a number of reasons.  See the help topic "When can I
update data from a query?" for a detailed discussion.