Hi isladogs
I have now read the first part of your article. It gave me a clue I had ignored before. I have not had "Delete records in related tables" checked. So it's done now on all relationships.
In the picture "Records relations" you see what my database looks like today.
I've done some screenshots that I hope will explain what's going on.
In picture 1 ("f_skiva1") you see what the form looks like with the first record. In picture 2 ("f_skiva2") I have clicked on a new blank post and got a blank form. Here I have now filled in a bit about the album I am going to register. When I move to the subform, the entry in the table "t_skiva" is created. So far so good. In picture 3 ("f_skiva3") you see what happens after I fill in the line and click on enter. Already after I selected the song in the second field, from the combo box there, a new entry appears in the field "t_låtar_musik_ID" and that is the problem. Even though I selected a song that is already in the table, it wants to create a new record.
It is important to know here that the first field in the subform is taken from the middle table which gives many to many relations between t_Låtar and t_skiva, the rest of the fields are taken from the table t_Låtar.
The last field must be filled in to create an entry.
The warning box says something like this: The changes you requested in the table were not made because they would have created duplicate index, primary key or relation. Modify data in the fields that contain identical data, delete the index or redefine the index to allow duplicates. Then try again ".
Hope I gave a little more to the problem now.
Leif