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

AnilRaghavan

Level 1

4 points

Posted on Feb 14, 2019 11:57 PM

Solved on 2018 MBP 13" with TouchBar to mid-2011 iMac 27" and late-2013 iMac 21.5". Using the Apple Thunderbolt cable, my iMacs easily switch Target Display Modes with each other .. just beautiful. But even with the Apple USB-C to Thunderbolt adapter and the same TB-to-TB cable, from 2018 MBP to 2013 iMac worked only sometimes and often did the flickering deal. To the 2011 iMac, all I got was a black screen on the iMac. Finally I remembered my company had given me a Belkin dock which I don't use since the MBP can drive 3 external displays by itself. Using the dock, I connected my MBP to the dock with a USB-C to USB-C cable. Then plugged in the USB-C to TB adapter to the second USB-C port on the dock. Plugged in the TB to TB cable to the adapter. Now both iMacs go into TDM easily and stay connected with no flicker at all. MBP runs High Sierra (I cannot update to Mojave yet, since it breaks some company proprietary apps), 2011 27" iMac runs High Sierra and 2013 iMac runs Mojave.

This is the dock

https://www.bestbuy.com/site/belkin-thunderbolt-3-express-dock-hd-silver/5947892.p?skuId=5947892&ref=212&loc=1&extStoreId=1501&ref=212&loc=1&gclsrc=aw.ds&&gclid=EAIaIQobChMI9ueqgJC94AIVWR-tBh0CGwL1EAQYASABEgK_i_D_BwE

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224 replies

mtraynor

Level 1

8 points

Oct 24, 2018 2:23 AM in response to Pennock

Pennock thank you, I read the post as the beta version of Mojave then current Mojave being the latest. I have signed up and download and this has worked 🙂 thank you

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.

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

It works after installing 10.14.1 beta 5.

Thanks a lot!

dnssolo

Level 1

8 points

Oct 28, 2018 11:22 PM in response to Pennock

Not true!! You can connect only from the bottom left C so no more two iMacs! The other 3 Cs do not respond.

Oct 29, 2018 1:22 AM in response to dnssolo

So your saying that bottom left USBc to thunderbolt 2 works on is 10.14 or that the beta 5 on fixed it to work in the left bottom USBc?

Oct 31, 2018 12:44 AM in response to WorldTravelingPhotoPro

With the 10.14.1 update only installed on my MacbookPro the dual screen and the sound through the iMac speakers works perfect for me.

Oct 31, 2018 3:09 AM in response to Pennock

Hi there

Did you get this to work? If so did you install macOS Mojave Beta 10.4.1 on both of your macs?

Cheers

Oct 31, 2018 3:16 AM in response to Studio1984

PS this was only ever an issue on the MBP 2018 15inch, which I have, tested it in the shop before the patch on the 13 inch and it worked, all fixed now on 10.14.1

Oct 31, 2018 5:09 AM in response to asherfromhawthorn

REAL (not Beta) 10.14.1 was released Tuesday, 30 October 2018.

55eba

Level 1

4 points

Nov 1, 2018 10:49 AM in response to TayDC

Audio in mine works.

My set up MBP 2018 Mojave 10.4.1 --> iMac 2011 El Capitan 10.11.6

mtraynor

Level 1

8 points

Nov 1, 2018 10:57 AM in response to 55eba

Hi have installed Mojave 10.4.1 on both devices so maybe that's the issue. I think others have done the same 😟

Nov 1, 2018 12:38 PM in response to mtraynor

MBP2018 with Mojave 10.14.1

iMac 2013 with El Capitan

It works fine

May you need to change target on Sound preferences in System Preferences.

By default is on MBP. You need to change it.

Dec 17, 2018 12:39 PM in response to Pennock

Has this issue been fixed yet? trying to use a 2018 iMac and a 2018 MacBook Pro and not able to get the thunderbolt to work.

Dec 17, 2018 1:18 PM in response to GracePoint

Mine was NOT working this summer but started to 2-3 months ago. Probably as the result of some sort of software update?

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2018 MacBook Pro Target Display Mode Not Working