After problems with upgrade, now problems with Mojave 10.14.6
On a 2012 Mac Pro, I made the mistake of installing the July 15 security update, which worked until I decided to install some new screensavers. Everything went to H___ in a H___B_____, but quick. Most noticeable was Stalling-whatever I was doing, no matter how basic and banal, the screen would lock up, the Wacom cursor would be immobilized, and even the mouse cursor, which was still moveable, would become ineffective. Then all my moves would show up at once, in a fraction of a second, and the Wacom tablet would be useable again. Until it stalled again, a few minutes later. Now, after I wiped the boot disk and reinstalled Mojave-which gave me a few problems-the OS isn't stalling, but it's become useless in a new and different way: everything crashes. If I open Mail, it opens, then crashes. If I try to restart in Safe mode, it doesn't work. If I simply select the upper-left-corner black Apple, to do a restart, or even shut down, or restart from a different drive, I am greeted by the spinning pizza of death, and then the Finder crashes. The black Apple logo is pretty much sacrosanct, no? It's inaccessible. I'm writing this on my MacBook Pro because the Mac Pro is now a boat anchor. Any ideas?
Mac Pro, macOS 10.14
