Photoshop Elements 2020 Organiser Catalogue Crashes

OS: Catalina 10.15.5

I have spent the last week organising and cataloging 10,000 photos into this programme so you can imagine how frustrating this issue is!!

I spent two hours with one of your support guys trying to resolve this issue.  To be fair he was very good and for a while it worked but the issue still reappears.

Almost every time I try to back-up the catalogue the whole programme crashes.

The source pictures are held on an external HD. I have tried the usual "reconnect missing files, disconnect hubs,create a different catalogue, repair catalogue".

I have also sent numerous crash reports to your engineers.  HELP!!!!

Thanks