MacSierra 10.12.1 Public Beta 1 broke dual monitors

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
So I use both thunderbolt ports on my Macbook Pro Retina for monitors.. on Friday of last week it was working fine, MacSierra 10.12

Sometime on Saturday I installed the 10.12.1 Public Beta 1, everything seemed ok until I came into my office and plugged both monitors into the 2 Tbolt ports.

My Left monitor never turned on. I unplugged and re-plugged a dozen times, nothing. If I unplug the active right monitor that is working, the left monitor turns on. This doesn't appear to be a hardware issue at that point. I boot into diagnostic mode and both monitors work. It generates a VFD002 error which I send to Apple.

Apple issues out 10.12.1 Public Beta 2 which I HOPE fixes the issue, nope.

So my left monitor no longer displays when plugged in. If I unplug the right monitor the left one turns on. If I plug the right monitor back in it never turns back on. If I unplug both monitors, I can plug either one into either of the 2 tbolt ports and the ports work perfectly fine.. it's just they don't work when 2 are plugged in. I've tried resetting NVRAM and SMC, nada.

EDIT: TL;DR - Both ports dont work simultaneously. I can plug my right monitor individually into either port and it works. I can plug my left monitor into either port and it works. If I plug both in, only 1 works.

Anyone else have this odd issue?
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
I did, the Public Beta 2? Yeah I installed that and it didn't fix the issue.
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
Nice, at least there's a post on their forums now so they are aware of it. I hope it's fixed soon.. Been using Beta's for awhile now and never once experienced a straight up broken feature like this before.
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
@mike666999 I have the exact same MBPR as you. I'm wondering if it only affects these models with the ATI M370X cards?
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
It did which is odd.. I have a few other Mac's on the 10.12.1 Beta 2 but none have dual tbolt ports for me to test this..
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
How long typically after the Dev's beta's do the public beta's arrive?
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
Public Beta 3 is available.. I'm downloading now. Will report back.
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
So annoying!!! It has to be a display driver issue because I can plug my tbolt to Ethernet adapter into the other tbolt port and it works fine. If I unplug it and plug my monitor back in it doesn't come on.
 

adamzeis

macrumors newbie
Oct 6, 2016
7
0
I'm having this exact issue as well. I just got dual displays for the first time yesterday, so I can't say that they worked previously, but they don't work together now. I can get either to work on it's own, but not both to work at the same time. I'm running a mid 2015 rMBP AMD Radeon R9, with two ASUS VS248 displays, both HDMI > Thunderbolt. Sierra beta 10.12.1.

I tried using one HDMI > Thunderbolt and the other HDMI > HDMI, but no luck there either. Still only recognizes one.

I was on the phone with Apple for about 45min yesterday and they couldn't resolve the issue.
 

sniffs

macrumors regular
Original poster
Jan 24, 2013
190
6
So you have the same laptop as the rest of us.. I'm wondering if it's an issue specific to this laptop. @drmito, what Mac do you have?
 
  • Like
Reactions: adamzeis