Frequently, when I try starting PM, it doesn't open a visible screen, and I can't display it even when using Command+Tab. I have to Quit and try again.
I am using the current version, and this was happening on both El Capitan and now on Sierra. Hardware is Late 2013 iMac 27" i7 with 32GB ram and 1TB SSD. Ditto on my MacBook Air.
This is most embarrassing when I try to show photos to customers!
How can this be remedied?