Macbook Pro Mojave won't connect to HDMI projectors + monitors

As I understand it, there are two possible causes here:

1) usb-c cables are not created equal. Some provide power but support only usb-2 (yes, not a typo) type of connections. That is the case (if I'm not mistaken) of the charging cable that comes with your power adapter.

2) support for usb-c displays. I have not seen it in writing anywhere; it is not clear to me if connecting a usb-c display directly is supported in macOS.

OMG finally, I've been trying to trouble shoot this issue for 2 weeks now! I pray someone can figure it out. I'm having the EXACT same problem. Before upgrading my MacBook Pro 2017 with High Sierra I did not have this problem at all. What the **** did Apple do with Mojave that now external displays don't work????

SMH

Hey everyone, I waited inside the apple store for3 hours (bcz of the holidays smh) to finally figure out why the HECK this was happening us - well, come to find out it’s actually our AV ADAPTOR that has gone bad and MUST be replaced.

I **** you not, I’ve tried EVERY SINGLE restart+buttons, and safe modes and etc etc etc. none of those are going to work if your dang device isn’t working in the first place.

Good news though, apple replaced my Multi AV device for free 🙌🏼🙌🏼🙌🏼

Hi I have similar problem as described by CorSat9 and others.

A Philips TV does not show up as monitor (no mirroring option, etc) when connected via USB-C to HDMI adaptor (Targus, 4K) in Mojave 10.14.3. None of the software solutions mentioned in this thread worked. Probably I'll need to try another adaptor, e.g. Lenovo.

Hi Luis. The Targus adaptor is just a simple USB-C to HDMI, not a multi adaptor. The Lenovo one I tried is a multi-AV adaptor. None of them works, with or without the displaylink driver (now un-installed it). Another, serious problem is that now, after SMC reset, whenever I try any of these adapters the MBP's keyboard & touchbar are disabled and the only button which works is the reset button. Frustrating.... I had a MBP for the past 8 years and never ever had these type of problems or hardly any problems...

Digging for more info ... It seems that not all USB-C to HDMI adaptors out there actually support the functionality called "DisplayPort Alternate Mode to an HDMI" which is needed when connecting an MBP to and external HDMI display. For example the "Club 3D CAC-1504 Active HDMI signal converter" does support it while the adaptors I tested do not (according to their description). It will be interesting to test this 'theory'. In case anybody on this forum thread has the related info of his/hers adapter and willing to share here, we could confirm it. In any case, I think I'll invest into one of these Club 3D adapters.

Everyone I had the same problem, there is NOTHING wrong with Mojave and there’s nothing wrong with your computer, the problem is with the Multi AV HDMI adapter and/or the USB-c to HDMI you are attempting to use,. I was using Apple’s multi AV adapter, which worked every day I used it before switching to Mojave and it was working fine, however, coincidentally after installing Mojave, it stopped working. Therefore, I assumed it was the multi adapter causing issues, but when I went to the Apple Store we tested my adapter and found out it had gone bad. So don’t get too frustrated, this only means that either your Apple adapter dongle has gone bad or that the cable you are using Needs to be replaced.

—hope this helps 🙌🏼🙌🏼🙌🏼

Well... I tested two brand new adaptors and none of them worked with my MBP but they work fine with a Win10 laptop. So, with my engineering mind, I must assume this is due to hardware incompatibility and, as always nowadays, all hardware runs some kind of firmware... Let's see what my 3rd adaptor has to say about it in a couple of days when I receive it. I'll certainly post the result here :)

Hello community!

In my case the problem is solved and it was _not_ a hardware problem. Here is what I did.

With the external monitor connected to the MBP through the USB-C to HDMI adaptor (it didn't matter which one [sic]), I opened System Preferences > Energy Saver and uncheck the tick box 'Automatic graphics switching'. When doing so, the OS automatically recognized the external monitor and the usual mirroring option became available in both the menu bar and also in the System Preferences > Displays. After this I switched back on (ticked the box) for 'Automatic graphics switching', which should be the normal way if using the dual graphic card systems. After these simple steps above my MBP recognizes the external monitor automatically every time I connect it, and without the need to switch off/on the 'Automatic graphics switching' option.

It seems the Intel graphic card was unable to detect the external monitor and only the AMD Radeon card could do so. After recognized once, the information about the external screen is probably stored in the NVRAM or SMC and can be used in subsequent occasions.

I'm not able to generalize this solution on my own. In any case this what & how it worked for me. I hope it will help others too.

All the best.

Hello community!

In my case the problem is solved and it was _not_ a hardware problem. Here is what I did.

With the external monitor connected to the MBP through the USB-C to HDMI adaptor (it didn't matter which one [sic]), I opened System Preferences > Energy Saver and uncheck the tick box 'Automatic graphics switching'. When doing so, the OS automatically recognized the external monitor and the usual mirroring option became available in both the menu bar and also in the System Preferences > Displays. After this I switched back on (ticked the box) for 'Automatic graphics switching', which should be the normal way if using the dual graphic card systems. After these simple steps above my MBP recognizes the external monitor automatically every time I connect it, and without the need to switch off/on the 'Automatic graphics switching' option.

It seems the Intel graphic card was unable to detect the external monitor and only the AMD Radeon card could do so. After recognized once, the information about the external screen is probably stored in the NVRAM or SMC and can be used in subsequent occasions.

I'm not able to generalize this solution on my own. In any case this what & how it worked for me. I hope it will help others too.

All the best.

CorSat9, the problem was exactly as you described it when I tried to

connect my Samsung HDMI TV to my Macbook Pro (15-inch 2018)

macOS Mojave 10.14.3.

My problem ended when I bought a USB Type-C to HDMI Cable;

Brand: Choetech, Model: CH0019; Resolution: Up to 4K(3840*2160)@60Hz;

Protocol: DisplayPort Alternative Mode (DP Alt Mode).

It is not an adapter but a 1.8 meter cable.

https://www.choetech.com/product/choetech-usb-c-to-hdmi-cable-4k-60hz.html

https://www.amazon.com/dp/B01LYS3Q5A/

Hi Elefantote.

Thank you. 😊

I have the feeling that the combination of a good adaptor hardware (DP Alt Mode) and a correct setting in driver/firmware for the dual-graphic card setup is the recipe for this problem.

I have also tried the 'reset the SMC' method (see https://discussions.apple.com/thread/7143053?answerId=28621228022#28621228022) but the mirroring still does not work.

istva-aal,

I believe your theory is right. Please check my post about the USB Type-C to HDMI Cable;

Brand: Choetech, Model: CH0019.

I have same issue:
I am trying to connect external monitor with USBC-HDMI but the display is not showing.