I have a Samsung S24C650 monitor and after upgrading my MacBook Pro (13-inch, Mid 2012 to High Sierra I cannot use the external monitor.

I have a hub that connects to the thunderbolt, and from the hub an hdmi cable that runs to the monitor.

The monitor works correctly, It is tested with a linux distro on another machine. The cable is fine (obviously) The hub is fine, tested with another Macbook 2015 model

The trouble started after upgrading to high sierra, initially the icons where not shown, computer failed to return from sleep (forcing restart) and last and most important the external monitor gets no signal.

When I plug the hub on the thunderbolt, Macbook's display changes (the computer does recognize that an external monitor has been plugged in.

I also have reFind install for dualbooting into Debian, when dualbooting into Debian the same thing occurs.

Any ideas welcome

Edit: Looks like this is an issue... https://discussions.apple.com/thread/8085619?start=0&tstart=0

  • Does it work without the Thunderbolt hub? You're using a public beta of an OS, maybe you should report the bug to Apple? – Todd Dabney Oct 14 '17 at 16:57
  • No, still many people seem to face the same issue discussions.apple.com/thread/8085619?start=0&tstart=0 – George D Oct 15 '17 at 14:57
  • Did the release version of MacOS 10.13 resolve this issue? – Todd Dabney Oct 30 '17 at 2:52
  • 1
    No, it fixed some issues with the icons bur this remains.... – George D Oct 30 '17 at 8:50
  • before installing other software is you hub mac compatible? My same problem (no signal on the external monitor but connected with vga thunderbold adapter) solved by purchasing an original apple adapter; but even with this when I reconnect the monitor to make it recognize sometimes I just have to move the connections – claudio Dec 11 '17 at 9:33

I just had the same issue. Found this link to upgrade the display port drivers, it was working again after a installing and restarting: http://www.displaylink.com/downloads/macos


I fixed the problem--by using an Apple TV device to create my extended desktop. It was super easy and it remembered to go back to the extended desktop setting when I turned it back on later.


Couldn't connect external monitor, drove me crazy. Solution: Used a VGA cable with a USB-C adapter and it works. HDMI and everything else won't. VGA cable + buy a VGA-USB-c adapter = saving a lot of money.

  • 2
    VGA is a seriously inferior standard than HDMI. While I'm glad this worked for you, this doesn't seem like it'd be an acceptable solution for most people. – JMY1000 Jul 23 '18 at 5:53

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