John, I restarted LR and subsequently the map module functions properly.
According to your experience, what it best practice for running LR - how often should the program re-started or when should it be quit? I use LR and other image software daily, but usually simply let the iMac sleep at the end of the day, waking it the next morning.
Normally I have LR optimize and backup the catalog weekly, then reboot the computer.