Lightroom classic, is unable to repair corrupt catalog

I have problems accessing Lightroom classic. It is updated with the latest version. 11.5.  I get the message that Lightroom is temporarily to repair corrupt catalog. I have tried to push the repair button but it just sends me back to this message after a second. I just updated my computer to macOS Monterey, and at the same time as Lightroom Classic stop working so did my external harddrive. I have tried to uninstall Lightroom and install again but with no sucess. Also I have made sure that Lightroom Classic has full disk access. Now I really need help - what more can I do? 
Best regards, R. Muts