I am working with an enhanced version of the NorthWinds DB that came with a
book from Microsoft Press. It does everything I need to do for a project at
work. However, I cannot delete the existing records in order to adapt it
for my use. I've used the Access utility to copy database structure to
clone the database using the "Definition Only" option, but it did not work.
(The utility did successfully clone another Acess database, so I know it
works.) Apparently, there is some addiitonal protection that prevents the
removal of its records.

When I try to remove the relationship between two tables I get an error
message that I can't delete relationships from "linked tables" from an
"inherited" database.

When I open a table in Design View I get a warning that the table structure
cannot be modified.

If I edit a relationship between two tables I can see that referential
integrity is checked, but it is greyed out, so I can't change it.

This database does everything I need it to do. All I need is to purge the
exisitng data and my project is done. Question: Does anyone know how to
hack into such a database so that I can clone the structure or delete the
existing records?

I don't particularly know Northwind, not having looked at it for many
years, but, it sounds to me as if the database is split into a
so-called "front end/back end" structure, where all the tables are in
the back end (BE), and everything else (forms etc.) is in the FE. It
sounds like you are trying to change relationships or table structures
in the FE. You don't do those things in the FE - you do them in the BE;
ie. the database containing the actual tables - not the one containing
the /links/ to those tables.

Does that help?
TC