I've changed (edited old ones) a few field Captions and the new ones don't show in new (or old) Datasheets. Captions for new fields show ok, but not the old edited ones. Is there a way to update these or do I have to create new fields?
That is very odd. I just tried what you did in both Access 2000 and Access 97 and both times the caption changed when I changed it at the table level. Is it possible that you have captions set at the query level as well? If so that would explain it since it would over-ride the table caption.
It is really only a problem if you are referencing the fields in code or in a later object. If the name of the field has changed then you have to make sure you are using the correct name and if there are spaces you have to put brackets around the field name. If you just want it to print out in a query than it is not really a problem.