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No signal on external displays after mojave update 2018

jesse550

jesse550

macrumors newbie
Original poster
Jul 13, 2018
14
8
So finally...got mojave installed on my 2018 MBP and now external displays do not work. These cables and dock were working perfectly fine before. Tested on another mbp as well and they work fine.

I tried nvram reset and smc reset...no beans. Also installed the latest displaylink drivers...no beans.

Anyone else experiencing this?
 
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jesse550 said:
So finally...got mojave installed on my 2018 MBP and now external displays do not work. These cables and dock were working perfectly fine before. Tested on another mbp as well and they work fine.

I tried nvram reset and smc reset...no beans. Also installed the latest displaylink drivers...no beans.

Anyone else experiencing this?
Click to expand...
I have the exact same problem with iMac Retina 2015 and Dell 2718Q 4k display - it just doesn't wake up. The only thing that helps is pulling the cable out and then back in. I am running PB2 on that machine. Maybe PB3 solved this issue.
 
Same problem on two thunderbolt displays running on 2018 MBP. Interestingly, audio on displays still work and peripherals plugged into displays (as well as Ethernet) do work. Just no display video signal.
 
My two LG 4K screens over thunderbolt to DisplayPort don’t work either after the Update.
(Made an extra Thread about that. I hope it gets deleted)
Anyone of you had success in the meantime ?
 
Uhu said:
I did not find a solution. Going back to HS for now after submitting the bug report
Click to expand...
Same. My 5K didn't work in Mojave, I filed a bug report and downgraded. I spoke with Apple support, and we tried some things, but eventually came to the "it's beta, so you're on your own". Works fine in High Sierra again.
 
stevespa said:
Same. My 5K didn't work in Mojave, I filed a bug report and downgraded. I spoke with Apple support, and we tried some things, but eventually came to the "it's beta, so you're on your own". Works fine in High Sierra again.
Click to expand...
me zoo. HS works very well
 
I didn't have any signal at all before regardless of what I did. Now my external display works. I haven't tried putting my computer to sleep and waking it though.

Update: Display still works after waking from sleep.
 
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Jdeck said:
Is anyone using an elgato dock and can confirm if it’s working or not?
Click to expand...

I bit the bullet and installed it. I have the elgato dock. I can confirm external displays are now working. Running 2 4k monitors @60hz with the dock
 
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makdeniss said:
I have the exact same problem with iMac Retina 2015 and Dell 2718Q 4k display - it just doesn't wake up. The only thing that helps is pulling the cable out and then back in. I am running PB2 on that machine. Maybe PB3 solved this issue.
Click to expand...
[doublepost=1538618744][/doublepost]I have the same issue on my 2017 iMac, I have a Dell 2718Q connected via thunderbolt and it has been working fine until I upgrades macOS with Mojave. Now I have to cycle power on the 2718Q every time after my iMac wakes up from a sleep. If there is a fix or a workaround, please provide, Thanks
[doublepost=1538618780][/doublepost]I also performed a PRAM reset but it dd not solve issue
 
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I have an old 21” Samsung LCD from 2005. It is hooked up to my 2012 iMac via a display port to DVI connector. It is acting odd under Mojave. It wakes and seems to work. But sometimes it will go through a period where an ‘Auto Adjustment’ message pops up on it. I believe this occurs when it first gets a signal. It can do this for a while and then stop. In my case it mostly seems to work but you have this annoying message that can last a while. Unless this is a coincidence of it going bad now there might be something off in Mojave in regards to external monitors.
 
njarif said:
[doublepost=1538618744][/doublepost]I have the same issue on my 2017 iMac, I have a Dell 2718Q connected via thunderbolt and it has been working fine until I upgrades macOS with Mojave. Now I have to cycle power on the 2718Q every time after my iMac wakes up from a sleep. If there is a fix or a workaround, please provide, Thanks
[doublepost=1538618780][/doublepost]I also performed a PRAM reset but it dd not solve issue
Click to expand...
couldn't find a fix for this. Tried different solutions including upgrading the monitor firmware through windows boot. The only thing that helps now is that after turn on / sleep I press the monitor source button multiple times -> select auto quickly and that makes the monitor work / wake up.
 
jesse550 said:
So finally...got mojave installed on my 2018 MBP and now external displays do not work. These cables and dock were working perfectly fine before. Tested on another mbp as well and they work fine.

I tried nvram reset and smc reset...no beans. Also installed the latest displaylink drivers...no beans.

Anyone else experiencing this?
Click to expand...

I have figured out that my external monitors only work when the connector has a power supply connected to the usb-c port. That wasn't a requirement before. Once I completed a SCM reset (held down cntrl+option+command+power button for 10 seconds after turning off mac) I could remove the powersupply, then I had to unplug the hdmi cord and plug it back in.
 
Last edited:
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jesse550 said:
So finally...got mojave installed on my 2018 MBP and now external displays do not work. These cables and dock were working perfectly fine before. Tested on another mbp as well and they work fine.

I tried nvram reset and smc reset...no beans. Also installed the latest displaylink drivers...no beans.

Anyone else experiencing this?
Click to expand...
[doublepost=1540018169][/doublepost]Yes, EXACTLY the same problem and have tried everything I can find to solve it - but I can't crack it. I do mean everything! I have an external LG 27UK850 4k monitor that worked perfectly before and now it will not connect to my Mojave iMac. It will connect to a TV tuner or DVD player and function perfecty in HDMI. But Display port and the USBC (the reason I dropped $900Aus on the monitor) has rendered my inverstment a total turkey. V5 of the DisplayLink software won't even load - no matter how many privileges I give it. It shows a proper Certificate from Apple but the splash sceen shows: "DisplayLinkDriver can't be installed on this disk. is Downgrade"

Come on Apple - what the hell is happenning to you. While your stuff is getting prettier it is getting more and more useless and troublesome with every release.

I NEED functionality, not a dead moniotor because I trusted you. No matter how pretty Mojave is - it doesn't work properly.

I NEED this monotor to work damn it! Digitus Extracus Apple.
 
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