MAJOR ISSUE: LG 31MU97-B 4K display and El Capitan and late 2013 MacPro(trashcan)

[patrickortman]

Hi All,

I own the above, and when I upgraded my nMP to El Capitan from Yosemite, all of a sudden, the LG display stopped working "correctly" with it.
That is, it no longer sees a signal when using either the supplied minidisplay-to-displayport cable, or a certified VESA-compliant similar cable (that was the first thing I tried). It DOES work with HDMI still... at a miserable 30Hz- not ok!

And the display works fine with my 2016 MBP using the same minidisplay port to displayport cables. No problem at all.

So I don't THINK it's the display.

Does anyone have any idea what's up? Yes, I tried making sure the "enable displayport 1.2" was ticked in the monitor's settings. And I've zapped the nMP's PRAM/nRAM and unplugged the power cable for a minute, to reset the system battery whatever thingie.

The nMP is still outputting a signal on minidisplay port, because I am using it right now to drive my HP dreamcolor 1080p monitor (sad).

Thanks for any help!

Patrick

 

[jake blackstone]

If doing something hurts, stop doing it:biggrinjester:
Roll back to Yosemite, problem solved. EL Capitan is an awful update.

 

[patrickortman]

Haha, so very true!!! I am considering it, the process isn't going to be easy: like most of you, I have a ton of plugins and applications and settings, and having now upgraded to El Capitan, you basically need to wipe your boot drive to roll back. Not at all fun.

 

[Jeff Kilgroe]

Er.... Always make a backup before you upgrade. I do a drive image so if things go wrong I can do just that -- wipe my drive and replace with the old.

That said, El Capitan in its latest release is pretty decent. As good as any Yosemite release. One thing with El Capitan I have found though is that it always glitches in some way if you do an upgrade. It's one of those releases where a fresh install is best.

 

[patrickortman]

Jeff, I think I've read some posts from you from a while ago where you were looking at this exact monitor for your own use? If so, is it working for you with El Capitan? It's just bizarre to me it stopped working on that update, yet works fine on my macbook pro. Thanks!

 

[Josiah Duncan]

Definitely fresh install every time. I had so many issues with Yosemite before realizing I hadn't fresh installed since before Mavericks, I'm currently running a fresh install El Capitan, and after the first major update everything has been running okay.

 

[patrickortman]

SOLUTION:
The first clean install of El Capitan , did a PRAM and system battery reset, and that did nothing at all. Then I downgraded to Yosemite. Still no joy. THEN, I figured, to fuck with it all, ordered a new monitor, and re-installed El Capitan (3rd clean install). For the heck of it, I connected the LG display. IT WORKED!

So, cancelled the new monitor, and we're back at it. Yay!

Thank you for your help, guys. Clearly there was SOMETHING weird in my system, but it appears to be gone, now.

P