Backup of PE2019 Catalog did not end as usual but no error message

After importing lot of photos from a vacation, I received a message that I had made enough changes to my (PE2019) Catalog on (Windows 11) that I should back up my catalog so I tried to. After I gave a location for the backup, while it was preparing files but before it gave any percentage complete, it just stopped. No error message. So I closed out of the program, logged off and back on and tried again. When I went to bed, the back up was 90% complete. In the morning Photoshop Elements program was closed. I just saw my desktop. There was not the usual message that the backup had finished and press enter to refresh. When I got back into Elements I received the same message that a catalog backup was recommended. So it looked like the backup never ran, but the new backup file is on my external hard drive. The last two lines of the backup file are .tly and .buc, as usual. What happened? I use a custom location for my catalog and it is on a different external hard drive from my photos, if that matters. Thank you for your help.