Retina iMac and external monitor: losing my mind

[cschmelz]

So I had a 2010 27" iMac that was flawless...Zero issues, external studio display, all worked perfect. Betas, upgrades, nothing caused an issue.

Upgrade to Retina 27" 2015 and the issues have been nonstop.

I continue to lose my external monitor....It just shows up black..One day it is fine, do an upgrade or something changes and dead..... Won't recognize at all, detect displays doesn't work, reboot without it plugged in won't work.

Reinstall OS, (not clean) and works fine....Until the next upgrade....

I installed this most recent time from a DiskMaker X USB drive which seemed to result in a stable system....Until I upgraded from 10.11.3 to 10.11.5...Now external monitor is dead...Again..

Thoughts? Makes my Dell Surface X2 (work laptop) seem reliable which is SOOO wrong...

 

[cschmelz]

So I had a 2010 27" iMac that was flawless...Zero issues, external studio display, all worked perfect. Betas, upgrades, nothing caused an issue.

Upgrade to Retina 27" 2015 and the issues have been nonstop.

I continue to lose my external monitor....It just shows up black..One day it is fine, do an upgrade or something changes and dead..... Won't recognize at all, detect displays doesn't work, reboot without it plugged in won't work.

Reinstall OS, (not clean) and works fine....Until the next upgrade....

I installed this most recent time from a DiskMaker X USB drive which seemed to result in a stable system....Until I upgraded from 10.11.3 to 10.11.5...Now external monitor is dead...Again..

Thoughts? Makes my Dell Surface X2 (work laptop) seem reliable which is SOOO wrong...

ADDENDUM: Reinstalled 10.11.3 from DiskMaker X USB flashdrive, now system works perfect. Updated to 10.11.5 and works perfectly. Here is to hoping......

 

[maflynn]

I'd look to do a clean install (not sure if you had done that), but it sounds like something his messing up the stability.

 

[cschmelz]

I'd look to do a clean install (not sure if you had done that), but it sounds like something his messing up the stability.

Fascinating thing is did a clean install of MacOS 10.12 Sierra on a fresh partition. Guess what? 10.12 beta does exactly the same thing!

I'm thinking this is a hardware issue and it may be time to take the machine in for warranty repair/replacement before it is too late.