Lightroom CC 8.2 catalog unexpected error

I was using lightroom CC and then I got this message: "the catalog could not be opened due to an unexpected error." Then I tried to repair the catalog in lightroom but it says this: "The Lightroom catalog is corrupt and cannot be used or backed up until it is repaired. I've tried choosing "repair catalog" but it doesn't work. There's a lot of work on this catalog that I need to access. 

I deleted the .lock file but I still encounter the error message and cannot open the catalog. I tried copying and renaming the .lrcat file but it didn't work. I'm using MacOS Catalina. 

 Thank you for your help.