2018 MacBook Pro Target Display Mode Not Working

I feel the same way, this has been an issue for too long now, and we haven't had any indication that is is an issue that they are working on. I just don't think it is a priority for them. I wish I had the will power to return this machine when I had the chance.

I hate that I have to consider buying a Thunderbolt hub to make this work...and would hate to do so prematurely if they do fix this down the road.

Sidenote - Those who do have the Thunderbolt hub/Target Display Mode combo working, which hubs are you using?

I had this exact same issue and after trying every possible cable and adapter combination I contacted Apple support. They took me through a bunch of troubleshooting and eventually escalated it to engineering. They were also unable to find a solution. After a couple of calls with engineering, I just bought another monitor and stopped trying to get it to work.

Hi, how did you daisy chained them? I have a La Cie Thunderbolt-USB3 drive and I plugged it to the 2018 MBP using the USB 3 and to the iMac using the Thunderbolt port, but nothing happened, am I doing this wrong? Thanks

The iMac is not just a display, so a connection between the iMac and the MacBook will be created only when you would like. You just need to press command + F2 on iMac keyboard. Then, you will see that the iMac screen is flickering. If you have already done that, and still you see nothing, try to check that you did all right according to the “Targret Display Mode” apple page. Hope it helps.

ibpatol wrote:

Hi, how did you daisy chained them? I have a La Cie Thunderbolt-USB3 drive and I plugged it to the 2018 MBP using the USB 3 and to the iMac using the Thunderbolt port, but nothing happened, am I doing this wrong? Thanks

The drive should have one USB 3 port and two USB-C Thunderbolt 3 ports. Use only the USB-C Thunderbolt 3 ports, one to the MacBook Pro, one for iMsc in Target Display Mode.

Be sure to use Thunderbolt 3 compatible cables (lightning bolt icons on the plugs). Short (0.5 m) cables can handle both USB-C and Thunderbolt 3. Longer USB-C and Thunderbolt 3 cables are different.

SWEET JESUS THEY ACTUALLY FIXED IT!! Update to Mojave 10.14.1 Beta 3 if you can to experience a sigh of relief. Side note I have not updated my iMac to Mojave yet and its still works so it looks like you only have to update the MacBook

I spend days now with this issue having Apple Phone and Mail Support. They know about it but they don't have an idea to solve it. In the the end I got the impression they don't really care to fix it. In my opinion this issue is not important to Apple. 😠😠😠 !

I bought my 13" 2018 MacBook Pro when they first came out and have been frustrated with Target Display Mode for so long. Now I can also confirm, the 10.14.1 Beta fixes the problem. I only downloaded it on the MBP and now it is working as smooth as butter. I am VERY VERY VERY VERY HAPPY RIGHT NOW! I will not go through the details of downloading the beta others have already done that in this forum - this is a good day. I hope the person that worked on the fix will be able to reads these very appreciative comments.

Still a SMALL BUG with Target Display Mode (TDM).

I updated to the macOS Beta 10.14.1 and I was very happy it worked. But when I tried to screen share the iMac I was using as the TDM monitor I only get a black screen. In the past I would screen share the iMac so I could still see the desktop but for most my work use the faster laptop to do my work. Right now screen sharing just shows a black screen. I sent in a report through the apple bata software program, we will see what becomes of it. Is anyone else noticing this?

I have this same problem with my MBP15 2018. but I am using a mid 2011 iMac 27". I've connected the two via thunderbolt 2 to thunderbolt 3 adapter. Both screens will go dark or flicker after pressing Command-F2. I hope this is resolved soon too

It's all very nice that for some of you it works after installling Mojave on the Macbook Pro. But for me it was not the solution. I haven't yet updated the iMac to Mojave, but after reading your replys I don't think it will really matter. I wonder why it works for some and doesn't for me....

It would be useful to know when the fix included in the beta version will be rolled out to a stable release. If I choose to update my machine to the beta version, will I easily be able to update to a stable version that contains the fix when it eventually releases?

I think there are two problems here. One was that if it did connect, it was glitchy (in HighSierra or early Mojave Beta)

The latter is resolved based on Peng Zhao on Oct 8, 2018. However there are likely a number of people who have since upgraded to Mojave OS (full release) still experiencing this. Someone mentioned getting a hub solved their problem. The reason that solved the issue, is that a lot of us are probably using Apple's Thunderbolt 3 to Thunderbolt 2 adaptor, and it, unlike previous versions Thunderbolt adaptors, does not support MiniDisplayport which is what are on the early model iMacs. Per this article How to Connect Your 2016 MacBook Pro to a mini DisplayPort Monitor

I recommend finding a cheap adaptor on Amazon or Newegg https://www.newegg.com/Product/Product.aspx?Item=9SIA7255RK7908&ignorebbr=1&nm_m c=KNC-GoogleMKP-PC&cm_mmc=KNC-GoogleMKP-…

I just updated my Mojave to beta 4 this evening and when you connect your 2018 MacBook Pro to your iMac, type Command F2 and the screen mirrors instantly. Works great. You then can drag you open screens over to the larger display without any problems. Connected with a mid-2011 iMac 27". Great to have the second display working.