Often many users encounter the message of two records with the same key. Either they select two or more sources or in someway duplicates are added. In this situation the program does not open the project and often the user doesn't know what to do. A potential new behavior is to show the message with the two records and source database file and let the user decide if to take first "yes" take second "no" or "cancel" (don't open the project).
We can discuss if this makes sense.