Due to a necessary re-installation of Windows 10 I had to re-install PSE 2019 as well. After that I tried to restore the catalog in Photoshop Organizer (PSE 2019) form an external disk drive. The Back-up File (*.tly) was found.
But I received the following error: "An error was found while restoring a catalog. It's best to contact your disk drive manufacturer to update on the latest firmware for your specific drive. Then try again." The external drive works properly. I found an old article about migration from between Vista en SP (