Level 1

59 points

2018 MacBook Pro Target Display Mode Not Working

Has anyone successfully used Target Display Mode with the new 2018 15" MacBook Pro? We just purchased one last week, and I am trying to use a late 2013 27" iMac as a second monitor via Target Display Mode.

When I hit command-F2 it does try to switch over, however the screen either a) remains black b) shows my screen but blinks every other second c) shows the screen but it's static-like and has crazy zig-zag colors across the background and flashes and such.

I have done all the recommended trouble shooting steps per the knowledge base article and am wondering if this is a problem with the new MacBook Pros. It is very frustrating to not be able to work on my brand new computer; I need the larger monitor for graphic design.

Both have latest versions of High Sierra. I have tried two different Thunderbolt 2 - USB-C adaptors. I have tried two different Thunderbolt 2 cables. One I have used for four years so I know it works. I have reversed the cables and tried all the different Thunderbolt ports on both machines. I connected them using Target Disk Mode to transfer my data and that worked.

I reset the SMC and zapped the PRAM. I booted in safe mode on both machines and then restarted. I have spent a good bit of time on this, but since this is a work machine I can't keep wasting time on it as I need to actually get work done, which unfortunately means still using the older iMac.

Any other thoughts?

MacBook Pro (15-inch, 2018)

Posted on Aug 2, 2018 7:53 AM

Top-ranking reply

PENG ZHAO

Level 1

18 points

Posted on Sep 12, 2018 1:15 PM

hey guys, just want to confirm that I used Belkin Thunderbolt 2 Express F4U085TT to connect my MacBook Pro 2018 with an iMac 2013. The iMac can be used as a target display. No flickering, no dark display. It just worked flawlessly.

Basically, you need a Thunderbolt 3 to Thunderbolt 2 adapter and the Thunderbolt 2 cable that comes with the dock to connect your MacBook Pro to the dock. then need another thunderbolt 2 cables to connect the dock to the iMac. I know it sounds stupid but it works.

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224 replies

Pennock Author

Level 1

59 points

Aug 2, 2018 8:14 AM in response to Grant Bennet-Alder

They are Apple, I bought them at the Apple store when we bought the computer. I needed one to connect to the iMac, and one to connect to a hard drive. I tested them using the hard drive and also using Target Disk Mode to the iMac and they worked fine for those purposes.

Pennock Author

Level 1

59 points

Aug 2, 2018 8:38 AM in response to Grant Bennet-Alder

I tried this, no luck. The MacBook does see the iMac, as soon as I hit cmd-F2 it shows up under Displays. I can also go into the System Preferences->Displays and can re-arrange the screen, etc. I can't really see the screen, or it's blinking and spazzing out, but the MacBook does see it.

Thank you for the suggestion!

Pennock Author

Level 1

59 points

Aug 2, 2018 10:26 AM in response to Grant Bennet-Alder

Haha! The iMac gets used 8 hours a day, it seems to be just fine. I'm wondering if it's an issue with the new MacBooks, not sure if anyone else has tried Target Display Mode with them. I did see one other report online of someone having the same issue, but that is the only info I could find.

TayDC

Level 1

28 points

Aug 3, 2018 5:39 AM in response to Pennock

I'm having the exact same issue. Trying to connect 2018 MacBook Pro 13" to a 2012 iMac in target display mode. It works perfectly on my 2016 MBP, but as soon as I plug in the 2018, my iMac display starts freaking out with the zig-zags you describe..really hoping that this is a software fix with the new models...

Storm988

Level 1

14 points

Aug 2, 2018 4:27 PM in response to HaraldS

The connection described in the question is valid:
Use your iMac as a display with Target Display Mode - Apple Support

iMac models you can use as a display	Cable you need	Port you need on your other Mac
iMac (27-inch, Late 2009)	Mini DisplayPort to Mini DisplayPort	Mini DisplayPort or Thunderbolt
iMac (27-inch, Mid 2010)	Mini DisplayPort to Mini DisplayPort	Mini DisplayPort or Thunderbolt
iMac (Mid 2011-Mid 2014)	Thunderbolt	Thunderbolt

Pennock Author

Level 1

59 points

Aug 3, 2018 5:58 AM in response to Storm988

Whew, good to know I am not the only one! My gut told me this was a problem with the new MacBooks, that's why I was wondering if anyone else had tried Target Display Mode with them.

I was planning on contacting Apple when I get a chance, I just have to find the time at work.

I hope this gets fixed soon, my boss will not be happy when he comes back on Monday and sees me still using the older iMac after we spent all this money on new machines. We had bought two, but the other one is hooked up to a regular monitor and is working great.

TayDC

Level 1

28 points

Aug 4, 2018 7:15 AM in response to Pennock

Same here, Apple is calling me back early next week and apparently with a senior advisor. Really hoping they will address the issue soon, as I would hate to have to return the machine only for them to release a software fix down the road.

And agreed, everyone should definitely contact Apple and raise the priority of the issue to them! I have also reached out to a couple Apple centric websites like 9to5mac to see if they would be interested in investigating the issue

Pennock Author

Level 1

59 points

Aug 7, 2018 6:51 AM in response to danny m

Make sure you report it to Apple, the more people that report the better. I haven't heard back from them so I will be reaching out again for an update. I sure hope it's not a limitation of the new hardware!

TayDC

Level 1

28 points

Aug 7, 2018 7:16 AM in response to Pennock

It seems like this affects all 2018 models by the sounds of it - which could be a good or bad thing, depending on if its software or hardware related. Apple is supposed to be calling me today to follow up so I will report back if I hear anything. Keep reporting the issue though, lets hope they issue a response!

TayDC

Level 1

28 points

Aug 7, 2018 7:59 AM in response to Pennock

Just got off the phone with a senior advisor, but they didn't have any answers for me. They kept telling me my 2012 iMac is incompatible with Target Display Mode...which it very much is, as it works perfectly with my 2016 MBP.

So I scheduled a Genius Appointment for Thursday - guess we will see what happens then

TayDC

Level 1

28 points

Aug 9, 2018 12:21 PM in response to Pennock

Well...just got out of my Genius Bar appointment, and the short answer was that Target Display Mode is "probably" not supported on the new 2018's. He showed me list of compatible iMacs and 2012 and 2013 are not/never were listed as compatible even with older MacBooks - which is untrue as I have 2012 iMac that works just fine with my 2016 MBP. So I have no clue what to do - I think I may have to return the 2018 MBP after all...

That being said he escalated my request to an Apple Engineer who will contact me with further explanation

TayDC

Level 1

28 points

Aug 12, 2018 3:02 PM in response to b3ntup

I have the exact same set up as you - and identical symptoms. It is definitely trying to work, screen freaks out, then stabilizes for a bit, then back to freaking out. And the display settings are available on the MBP, which leads me to believe the feature was not removed - but instead a hardware or software issue, hoping for the latter as I have 2 days to return this machine...

Pennock Author

Level 1

59 points

Aug 13, 2018 6:08 AM in response to Pennock

More people have clicked the 'I have this question too' button, which is good! Keep up the reporting to Apple! I also directed their support staff to this thread. If we keep it up they will recognize this is a universal problem with 2018 MBP's and maybe release an official response and hopefully can fix it!

There are people who want to return these machines because of this, so I would think that's a big deal to Apple. As more people buy them it's only going to get more widespread. My expensive new laptop is just sitting here unused as I need the big screen to work 95% of the time, it's been weeks now of wasted money. I would think they should have enough reports by now to start to realize this is a real problem.

TayDC

Level 1

28 points

Aug 13, 2018 1:28 PM in response to Pennock

Same here! I am impatiently waiting for a response while my machine collects dust, and I only have 2 more days until I have to return it, I am quite surprised that they haven't responded at all to what seems to be a widespread issue..really hoping to hear something soon

Aug 13, 2018 7:08 PM in response to Richard Fernandez

Yeah I actually have one that works great, it’s just the usb c to thunderbolt 2 adapter that doesn’t work for me. I just liked the simplicity of the ports being built into the computer when you’re carrying it around.

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2018 MacBook Pro Target Display Mode Not Working