I purchased Photoshop Elements 2020 to run on a Macbook Pro running Catalina 10.15.7. All of my pictures are in the previously purchased Elements 2019 Organizer. When I tried to open the 2019 Organizer, I get a message that Organizer isn't currently licensed and I should launch Elements Editor to update the license. When I launch Elements Editor, nothing happens. Is there a way I can open the 2019 program so I can refer to the pictures as I reload them into Elements 2020? I knew there were some compatibility issues, but nothing like this.
"All of my pictures are in the previously purchased Elements 2019 Organizer."
No, the pictures and the catalog folder are not in the "Organizer", they are where you put them on your computer; the catalog simply manages links to their real location and path.
If I am right in thinking that you have installed PSE2020 and the Catalina OS version on the same computer, all you have to do is to convert the catalog to the new PSE2020 catalog format. Use the menu File >> manage catalogs; click on the 'convert' button and select the last catalog in the dialog that opens. If you don't find it on this list, you can browse to its real location with the option 'more'. You get the default location of catalogs from the menu Help >> System Info. Your PSE2020 catalog has been created there by default.
The conversion creates a new catalog and the old one in PSE2020 format is renamed with a -1 suffix.
If you have migrated to a new computer with Catalina and PSE2020, read this: