Thanks for your reply.

The two apps that were affected most recently were scriptwriting apps. But the strange thing is that once I get them to open, they then behave normally.

Two days ago I downloaded (twice) a little app called MacPilot that I was never able to open at all.

What I would like to understand is why this is happening at all. I switched to Mac a little over two years ago and never had this problem until recently. It is nothing compared to all the problems I had with my PC but I would sure like to understand where the problem lies.