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

Oct 28, 2018 6:10 AM in response to asherfromhawthorn

I confirm: MBP2018 with Mojave 10.14 (installed today) doesn't work for me on target display with iMac27".

I have original connector USB-C to TB.

Aug 2, 2018 8:28 AM in response to Pennock

Try sleep and wake the MacBook Pro and see if it finds the display attached.

If not look in

 main About this Mac > (System Report) > ???

??? maybe ThunderBolt? Graphics&Displays?

... to see if the iMac is detected as present in some form

Pennock Author

Level 1

59 points

Aug 15, 2018 1:44 PM in response to chapimex_3

chapimex_3, have you opened a support case with Apple? I don't know if this information could help the engineers figure out this issue and fix it. Somehow the hub keeps the signal clear for a little bit. With a direct connection the longest I've been able to get a clear signal for is maybe two seconds. Every report made will also help show that this is a widespread issue.

Aug 19, 2018 10:07 AM in response to Pennock

I just got a 2018 MacBook Pro 13" and tried connecting to my late 2013 27" iMac and got the same results. At first I thought I had a faulty Apple TB2 to TB3 adapter. But it ran fine (although a little slow) when I used it as a Target Disk mode connection to a 2015 MacBook Pro 15". I also thought that is might be that my 13 is running high sierra while my iMac is only on sierra, but that doesn't seem the case, because target display works fine with my work 2015 MacBook pro 15" (and its running high sierra).

I'm hoping this is resolved with a software update. Hate the fact that I can't use my iMac as a monitor for my new toy.

Aug 27, 2018 7:07 AM in response to Pennock

I have used Target Display Mode with a 2013 iMac and a 2016 MacBook Pro via thunderbolt cable, with no problems, for two years. It is only when I tried connecting my new 2018 MacBook Pro that the problem arose, the same one everyone else is reporting. I'm fairly confident this is an issue with the new MacBook Pro

Pennock Author

Level 1

59 points

Aug 29, 2018 7:36 AM in response to Maverickos0815

Maverickos0815 - I would make sure you open your own ticket as well, I wouldn't rely on the Apple Genius to do so. Even if they do open one too, the more tickets opened the better!

It doesn't sound like anyone has been given any real answers yet, or that Apple has acknowledged this as a universal problem and just keeps treating it like an individual problem by wanting us to test cables and partitions and things which we have all seen doesn't work.

My MBP is at work, I'm hoping to get a quiet moment in the office to call again and push the issue some more. Everyone just keep calling or sending chat messages to Apple support.

I had also tried reaching out to some Apple news sites but I didn't get any response. If others did the same maybe one of them would pick up the story and help put some pressure on Apple.

pg@cfit

Level 1

4 points

Sep 4, 2018 1:17 AM in response to Pennock

The report in Radar has been marked as "duplicated" and "open", so its seems there's some engineer at Apple working on this. Hopefully we'll get a fix sooner rather than later.

Pennock: I will take it to the Apple Store... it's just a matter of getting the appointment on a weekend... which has proven difficult.

Sep 6, 2018 7:26 PM in response to Pennock

I have the same problem. I use my 2011 iMac (running on High Sierra OS) for target display to MacBook Pro (Retina, 15-inch, Mid 2014). The iMac was running very smooth as my target display. A few days ago, I just got 2018 MacBook Pro (running on High Sierra OS version 10.13.6 (17G2307)) and it's no longer able to connect to the 2011 iMac. After I read the discussion here, I chat with the Apple support. He told me to use Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter. I will get this cable tomorrow and will give you an update.

Sep 7, 2018 12:30 PM in response to MusicianProducer

Update: I returned my MacBook Pro 2018 15" after encountering a number of different problems. I bought the iMac Pro and target display works beautifully!

I would return your MacBook Pro 2018s and wait for Apple to get it together.

Sep 13, 2018 9:27 AM in response to Pennock

I also have this problem.

Brand new very pricey MBP 15" i7 with T3 connectors.

iMac Late-2009 27" with mini display port.

iMac still works fine as a 2nd screen with my old MBP 2012 13" via it's Thunderbolt (1?) port, running a mini display cable to the iMac's mini Display port.

In the new setup I am using the Apple T3-T2 adapter as per advised on this; Use your iMac as a display with Target Display Mode - Apple Support

And doing everything I can but it ain't showing up.

I'm currently chatting to a senior Apple support person after was fobbed off with 'go to Genius bar' earlier.

I will report if there's news.....

katbay

Level 1

8 points

Mar 2, 2019 9:02 AM in response to dom63

This is a long thread, but you may find your solution. There are multiple solutions that people found for their setup. For me, I also have the mid-2011 27" iMac. I use it with my 2018 MBP with touchbar. My solution involved going back to my original keyboard -- not using my third party keyboard which did not recognize the key commands. But I now have to have that keyboard sitting on my desktop for the sole purpose of using the iMac monitor. Apple should upgrade the OS to auto-detect connected devices, ask what you want to happen, then remember the setup.

Aug 13, 2018 6:58 PM in response to Pennock

Many people have reported this same issue. I recommend you contact Apple Support directly so that they have a record of many users with the same problem on these new MBPs.

bigron82

Level 1

4 points

Sep 2, 2018 12:43 PM in response to JeffQ6

I can corroborate this. I've just daisy chained my 2018 MBP through my WD thunderbolt RAID drive and, after a restart of the 2011 iMac, TDM works fine and exactly as I's expect it to.

Sep 10, 2018 8:53 AM in response to Pennock

I would also like to know what product information of that Belkin, please. Apple Thunderbolt 3 to Thunderbolt 2 adapter, never work with 2018 MacBook Pro.

Oct 28, 2018 2:25 PM in response to mtraynor

It works after installing 10.14.1 beta 5.

Thanks a lot!

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2018 MacBook Pro Target Display Mode Not Working