Currently, this thread has over 250 entries. This may be the longest thread in the forum. The solution to the corrupt catalog problem is so simple, yet time and time again here we are. I almost wish Victoria had not made the option possible. I have not made an analysis on the success rate of repairing corrupt catalogs, but I would guess that the number of successful repairs is small.And the moral of this story is, "Back up every single time you shut down Lightroom." If you quit for the night, that's a great time to do the shutdown.
Some people keep old backups going back months. I think it was Clee who said he had to go back six months to rectify a really bad issue involving the catalog. A 4TB external drive costs less than $100 these days. Western Digital Desktop External Hard Drives | Newegg.com.My corrupt catalogue did not result from not backing up. I backup every time I exit Lightroom Classic.
I have a removable 2TB Seagate expansion drive which holds my photographs and LRC catalogue and move this drive between a laptop and a desktop PC. I have a main backup of the catalogue and photographs on the desktop PC and when I am away from home a backup of the photographs I had been working on, on the laptop.
I had been away from home and had been working on the PC. When I got home I connected the removable drive to the desktop to backup the catalogue and found the catalogue folder on the removable drive was corrupted. The catalogue folder also contained the Lightroom exit backups and they were also corrupted.
I then realised how stupid I was to hold the catalogue and its backup in the same folder. In future I will continue to save the catalogue to the removable disk but will save the backup to the internal drive of the PC.
I have a backup copy of the catalogue on my desktop PC but it is about a month old.
It was my process which was the cause of my problem not that I was not backing up.
I do not know what caused the catalogue folder corruption but I do strongly suspect Lightroom.