Additional information: if I use an event to try and force it to Go To New Record, I get the message  "You may be at the end of a Recordset"

I'd suspect the form's underlying query first, because you can already add records directly through the linked tables.

The first test is to open the query itself in Datasheet View and try adding a record. If that also fails, changing the form's Allow Additions setting won't resolve it.

I'd check these points:
    - Primary keys included in the query: Microsoft specifically identifies missing unique-index fields from linked ODBC tables as a reason a query cannot be updated. Include the primary-key fields from the linked tables in the query output; they don't need visible controls on the form.

    - Joins and query properties: Check for missing joins, DISTINCT (Unique Values = Yes), totals, or grouping that could make the query read-only.


    - Form Recordset Type: Check that it is Dynaset, rather than Snapshot.

As a further test, you could create a simple form bound directly to the main linked table.
If additions work there, that further narrows the issue to the original query or form configuration.

The "You may be at the end of a Recordset" message doesn't establish the cause.
Forcing navigation won't overcome a record source that doesn't permit additions.

Thank you Kevin, once I included the Primary Keys from all the linked tables in my query, the new record option was now available in the query. When I then checked the form the new record option was also available. I very much appreciate the help