- Aug 22, 2013
I have an old mac pro down loaded mac os sierras by mistake from Mojave how to undo . When I turn on it just stays in start mode after I put in pass word the black line is all black and doesn't show the program starting to run. How to get back to el Caption something older? No back up except from time machine last one said aug 2018. Had a cast on hit button by accident.