Unfortunately, in copying a contact file from my primary PC to a backup, I used a new file name (simply changing the date). Unfortunately, where I had 400+ contacts in the back-up to start, I now have 800+. Instead of replacing the old contact file when I imported an updated one, it added the 2nd contact file..............creating 400 duplicates. Any suggestions for an easy way to eliminate the duplicates? The "clean up contacts" button remains grey in color, and will not respond to a click.  

A second question is -Can I go into the software and delete the 2nd file I imported? Let's say file #1 was named "backup10-11-12"  and the second file was "backup10-15-2". Can I delete the latter to eliminate the duplicates?