External monitor problem iMac 2017 High Sierra.

Same problem here with brand new Air. I've got 2 external displays, one through thunderbolt which is working ok and one through j5create usb display adapter which is black, only mouse pointer visible.

Got this answer from j5create support:

Unfortunately, our USB display and Ethernet adapters, as well as our docking stations, are not currently compatible with the new Mac OS X High Sierra 10.13 operating system

....

The current ETA for the new driver software is later this week!

So far since it has been a week without a single issue using the HDMI to lightening port adaptor I bought it for $24 dollars at Best Buy and has been stable. I won't pretend this will resolve everyones issue but in my situation it did I also feel that the new LED monitor does help I would have tested it with an older dell 21" but they didn't have HDMI support.

Thanks for the DisplayLink driver. At my workplace, we use wavlink, but did not see any updated drivers for macs. I installed the driver above and was able to have dual displays (MAC laptop and Dell monitor), but was unable to use the mirror feature on the mac or it would log the user out and reset to dual display. Hope this helps!

http://www.displaylink.com/downloads/file?id=1033

I'm having the same problem since I upgraded to High Sierra with a Samsung monitor(TV). I have to unplug the HDMI then reinsert it to get it to work.High Sierra doesn't remember all of my monitor settings on startup. Very Funky! I hope Apple is on this.

Different people seem to be having success by doing a number of things, although mainly updating Displaylink drivers if you run your multiscreen setup through a hub. I don't and simply connect USB-C through to HDMI via a lead. To date I have only found two ways of solving this problem. First is to unplug and reconnect my second screen each time the computer goes to sleep and the second is to go back to Sierra where everything then works fine. I have 2017 iMac and a new Acer monitor if that helps. Resetting VRAM etc.. seems to offer a temporary fix for a day or so, but as sooner as think its fixed I go back to the Blue Screen of Death on my second monitor. I suspect Apple would like everybody to move to a USB-C connected monitor which I bet would solve the underlying issue but finding one at the moment is hard and they are way too expensive. It would be good to find out from anybody if this does indeed work so at least we would all know their end game.

Guys! I found the solution!

I have a iMac late 2013 and I have two external monitor. 1 24 pouces (1200 x 1920) and 1 25 pouces (2560 x 1440). I disconnected the 24 pouces (1200 x 1920), allowed the "monitoring copy" (don't know how to say it English, it's when both screen show the same screen) and so I was able to change the resolution to 2560 x 1440. Then I disabled it and here we go! 🙂

Everything works fine for me right now.

I just fixed my issue finally.

I am using a MacBook Air

My symptoms:

The extended screen will go gray but i can still see the mouse.

In General, the extended monitor needs a third party program for it to work on the MacBook Air. it's called Displaylink

Everything was fine till the upgrade to High Sierra

My extended screen spec:

AOC e1659Fwu 15.6" USB 3.0 Powered Portable monitor w/ case.

• 1366 x 768 8ms (GTG)
• 500:1
• USB 3.0
• VESA Mountable 75 x 75 mm

Solutionnnnnnnn:

Reinstalling High Sierra didn't work.

- i removed Displaylink, ( uninstalled the third party old version, installed the latest version ) looks like i was using an older version of Display-link and I installed the newest version for Display-link and that worked yayyyy😁 I have the link listed below:

http://www.displaylink.com/downloads/file?id=1085

Sooo I am assuming whatever portable extended screen you're using, does it use a third party software??? if it does, go ahead and use the latest version and that might fix it instead of reverting back to an Older OS.

Thanks.

Youssef

Yep the only way I can get it too work is by unplugging it and plugging it back in. Otherwise its the blue screen of death.

How did you get on? Have you seen this?

http://support.displaylink.com/knowledgebase/articles/1188004-macos-high-sierra- video-functionality-not-enabled

Only thing that works for me is-to unplug the monitor and plug back in. That doesn't mean turn power off with button or remote

Mark W Green MD, FAAN

Professor of Neurology, Anesthesiology, and Rehabilitation Medicine

Director of Headache and Pain Medicine

Icahn School of Medicine at Mt Sinai

Vice Chair of Neurology for Professional Development and Alumni Relations

5 East 98th St, 7th Fl

New York, NY 10029

Ph 212 241-8168/7076

Fax 646 537-8513

Mark.green@mssm.edu (work)

Paininhead@me.com

Hello Johan

What type of connection do you have to both screens?, can you please share a photo, thanks

didnt work for me; actually all the adapters I got failed too. Only thing that helps with my mac pro is to unplug monitor and then replug

Also having a problem after updating to High Sierra. I have one display connected with displayport and a second display connected with HDMI. I cannot get them to work at the same time. The mouse cursor is displayed on both, but one of the displays is always completely black. Which one works seems to be random and changes when I unplug one of them and then plug it back

I have this issue too on my late 2013 MBP after upgrading to High Sierra.

The issue is only with the 2nd thunderbolt port. The 1st one works fine.

If I plug the monitor into the 2nd port it detects that there's something there and just tries to initialize it constantly and never succeeding (literally the screen turns on, detects no video source and turns itself off... then mbp turns it back on, and the loop repeats itself). I haven't tried the HDMI port, mostly because the monitor doesn't support 4K properly on HDMI.

I also have an ethernet dongle that only works in the 1st thunderbolt port and not the 2nd.

It's not just a display issue.

Well if you are unable to use a Time Machine backup you are also able to reinstall the version of OSX that you Mac shipped with via the recovery/safe mode options. Might be a couple of versions back perhaps but would save you money.