Thank you for your quick reply. That is useful to know. I will watch the video to learn more about preserving user settings..
As it was, I remembered that I had a fresh backup copy of the program installed on a another hard drive. I uninstalled the corrupted version with App Cleaner and copied the fresh version back onto my work disk. The program now works perfectly and it only took a few minutes and I have no more issues.
I'm not sure why I didn't think of it before ????…….Fredzheimers perhaps…..
Thanks again…..