Q: Multiple Monitors Not Working/Slow Startup
Can't get multiple monitors to work in Sierra on Mac Pro (2013). I've tried all the usuals like restarting, PRAM, etc. with no results. I have a TB Cinema Display and two Dell 23" via mini display port/VGA adapters. They will all work individually, but not at the same time. The Mac does not recognize the monitor unless attached at boot up (ie: not hot swappable). Just to note, I also have a TB HD attached and two printers via USB. I've disconnected them to see if they were the issue and same result.
Also, it takes several minutes to boot up and I get some weird artifacts on the screen during the process.
As a side note, I've also installed Sierra on our media machine Mac Mini (2011). Runs fine with no problems and has a 20" Samsung monitor and Samsung flatscreen TV attached.
I appreciate that we no longer have to pay for the OS, but quality control has gone to complete (bleep).
Going back to El Capitan.
Mac Pro (Late 2013)
Posted on Oct 2, 2016 7:58 PM