This is not normal Access behavior. What is your button code?

If a record is being created you must be setting a value on the form. Set it as a default value instead and a record won't be created.

Example:
MyField.DefaultValue = Value

Hi Kevin,
I had PersonF form opened. I then clicked a button on it to open CardF form. They are linked by PersonID. When values are added to the CardF, a record in CardT is created. The problem was when I decided not to put values into the CardF, and closed it, a record was still being created in the CardT as a it had recorded the PersonID.

I had set the default value for PersonID (the Foreign Key) in CardT = Forms![PersonF]!PersonID.

After seeing what you wrote, I made the following change:

I have now changed it to = if([CardFront]=Null Or [CardFront]="",Null,[Forms]![PersonF]![PersonID]).

It seems to have solved the problem.

Thanks.

I rechecked what I did, and my solution didn't fix my problem. What seems to have fixed it is I placed a file in the directory I was referencing, and it stopped the problem.

I recommend using default values if possible, as Kevin suggested.