Solution found!The bug I linked to above suggested it was something with the Mac Keychain, and indeed I'd had a bunch of crap in there that I'd been meaning to clean out.Long ago I had added keychains from another user account I was trying to recover...
Fortunately the bug i linked to above shows that it has developers' attention. Though to be honest, this bug is such a show-stopper, I don't know how 137 was released. I'm curious how prevalent it is.
Me too... strangely in a different user account, Firefox is fine, but on the primary one, which has lots of tabs open, it seems to be spinning out at the DNS resolution stage of a page load, and also hangs when you try to quit. macOS 15.4.Actually I...