not able to update related records in a many to many relationship

[Linda]

I have a many to many relationship with 2 tables through a
3rd table with the primary keys from the two tables as
primary keys in the 3rd table. The primary keys in the two
tables allow no duplicate values, but in the 3rd table
those keys I have set to Indexed-(yes duplicates). When
entering new data into either of these two tables, I then
open up the plus sign for the related table to enter in
the relationship, a message comes up saying that the
changes were not successful because they would create
duplicate values in the index, primary key, or
relationship. I now have no way of relating these two
tables to each other. I really need help.
Thank you,
Linda

 

[John Vinson]

When
entering new data into either of these two tables, I then
open up the plus sign for the related table to enter in
the relationship, a message comes up saying that the
changes were not successful because they would create
duplicate values in the index, primary key, or
relationship. I now have no way of relating these two
tables to each other.

Rather than using table datasheets for data entry - as you can see
they are of VERY limited capability - use the tools Access provides:
Forms.

Create a Form based on one of the "one" side tables, with a Subform
based on the junction table. On this Subform you can put a combo box
to select the desired value from the other "one" side table. See the
Orders form in the Northwind sample database for an example of how
this can be done.