I just got back from the Apple Store. After a LOT of diagnosis, they traced the problem to failed RAM. They removed the RAM and the problem disappeared. I'm writing this post on the rejuvenated Mac Pro. What a relief! Thanks for helping me decide I needed to go to the Apple Store. It really did require their diagnostic capability. I was resisting going because the Mac Pro is such a heavy beast to haul from the parking place to the store. <grin> Apple folks kindly helped me move it from the parking lot to the store and back to the car. I call that super service.
