LR Classic not opening. Macbook Pro, Tahoe 26.6. I have tried various options, including reinstalling the software and restarting the app, testing catalog integrity etc. Any suggestions?

Many people report that when Lightroom Classic doesn’t open, you just let it run for an hour or 3 (one person said it required 12 hours), and it opens and works properly and then it opens properly after that.

PS:when you post a question here, the first dialog box is for the title (although it doesn’t say that) and the second dialog  box is for the detailed description. We don’t need the same text wice.

Used LR for a decade without issue. Happened out of the blue, without any external obvious issues.