I posted the original question. I gave up. I tried everything that was suggested and had two IT pros work on it for about 2-3 hours each. I tried reaching Block, but I cannot stay on hold for the better part of my remaining life. No one found an answer. I then purchased the 2019 H&R Block business download to replace the existing program on the computer, hoping that maybe they had patched the problem. No such luck plus it overwrites the existing program automatically, so it wiped out all the atx files. Best Buy refuses to reimburse me for the software.
I also have a Carbonite subscription for backup to the cloud. They searched my files back to June but could not find any business program atx files. Another 3 hours shot.
My solution going forward was to purchase a new laptop and install the program from the disk that I already had. At that point, I had to use my PDF's and paper copies of the 2018 returns and re input all data. Program works fine on the other computer, so I question why so many other people had the same problem that I had for 2018 and 2019. I now print to PDF every client file including all support schedules, as well as doing a "backup" of the file instead of a "save as".
Overall, my experience was very disappointing and a complete time and money waster.
Block still has the best priced option out there, especially for business returns, but trying to deal with them has been a nightmare.