Macbook 2016 HDMI output flickering

Hey Mayank

I have the LG 27UD88-W monitor which also connects over USB-C.

Things have improved since installing the macOS 10.12.1 update (I no longer get flickering or the displaying reverting to 30 Hz refresh rate), however I still get:

1) 'No signal' message on the monitor when connecting the MacBook (even though the MacBook is receiving power from the monitor over the USB-C connection)

2) Crashes / kernel panics when connecting the monitor (which cause the MacBook display to go black and require holding down the power button to restart)

I get this about twice a day at the moment. Restarting the MacBook gets things working again (as seems to be the case with the HDMI issues reported here).

I am pleased Apple are reaching out trying to solve this issue, but fundamentally it does not sit right with me that the largest and most valuable computer/tech company in the world is no longer producing its own external displays. The whole reason I buy Apple products is the 'it just works' philosophy. In this case they are forcing users to purchase third party products (not to mention numerous adaptors and docks) and endure these kinds of problems.

Even if my LG 27UD88-W+Macbook set up correctly worked properly it would still not achieve the main features of the five year old Thunderbolt Display such as:

- Integrated speakers

- Integrated FaceTime camera

- Powered USB ports

- Ethernet connection

- Proper integration with macOS, allowing brightness and other settings to be controlled via the OS

Connecting an external monitor is not a niche use case. There are millions of Mac users that work with external displays: Apple needs to fix this.

Just wanted to report that my 2016 MacBook exhibits the same behaviour when attempting to connect to a BenQ GW2765HT LED IPS 27 inch Widescreen Multimedia Monitor via a HooToo Shuttle 3.1 Type C USB Hub. The display is 1440p and it flickers, slides in-and-out and sporadically blacks-out completely.

After turning the MacBook off and on again, with the HDMI cable connected, the issue seems to disappear.

Gutted!

Obviously, I'm hoping this can be fixed via a software update.

P.S. I looked at buying a Dell XPS 13, but opted for the MacBook. The XPS is looking pretty good right now, doh.

I hear you!! If it weren't for iMessage I'd be off.

..the more I use Windows 10 the more I actually find myself liking it though. What do I really miss? iMessage, iPhoto - that's about it really. Both of which can be used from an iPad, and the latter probably suits the iPad better anyway for editing purposes.

Just to input I've suffered similarly. I've now effectively had 3 2016 MacBooks all with the same flicker issue:

1. Original purchase developed a keyboard fault

2. Apple fix of keyboard fault resulted in main board failure and replacement

3. Reported the flickering issue and was given a brand new MacBook

Admittedly the number 2. machine likely did have the same USB-C port assembly as number 1. Either way all of them are unusable on an external monitor with random flickers and slide ins and outs.

I've tried the following adapters:

- Apple AV multi adapter

- HooToo

- VTIN

All the same problem. With regards to monitors that I've tried:

- 1080p Dell

- 1080p Samsung

- 1080p Iiyama

- 1440p Dell

Can provide model numbers if necessary. I've tried various HDMI cables, as well as HDMI to DVI. All the same problem.

I've now basically given up using an external monitor which is not the answer my neck is looking for long term.

I've not tried going back to Apple Support on this yet but will try to this side of Xmas.

FYI reboots and SMC resets sometimes seem to help but give it long enough and at some point it (the video signal) will flicker off and I'll lose patience again.

I kinda love and kinda hate my MacBook. So much to love but this USB-C video implementation is clearly brutally flawed.

I also am having the no signal issue, which requires turning my monitor on and off until it's recognized. Once it's recognized, I get screen black outs that occur while connected to an external monitor. Just prior to the screen blacking out I've noticed the mouse cursor becomes erratic and the system slows down like it's running a lot of cycles the the background.

If I detach the computer from the monitor without sleeping the machine, it often crashes and becomes non responsive. Also I have a 50-50 chance of crash on wake if the machine is connected to the monitor.

This all makes me think my issue is software/firmware related, hopefully, but who knows.

I'm curious to see if this problem amplifies with the new MacBook Pros.

Completely agree with this set of comments, and I have exactly the same issues with my 2016 MacBook and USB-C LG monitor

I can understand Apple stepping out of the monitor game, however disappointing that might be for pro users. Speculating, but it may be that that they have concluded that modern third party monitors (made by people like LG) are good / full-featured / well-designed enough that Apple would not be able to make one that much better. They would have to end up charging twice as much for the same functionality and slightly better design, so the proposition doesn't make sense.

However - they have taken the decision to go all in on USB-C as the output on all their latest and future laptops. Before doing this, they should have ensured that the technology was capable of properly running third party external monitors.

Now we're left in an extremely annoying position - invest early in Apple's latest laptop, but have no Apple monitor to pair with it, and flaky connection to all third party USB-C monitors.

I assume this will be fixed in a future software update, but it really should've been ready to go out of the box when they launched the first version of the new MacBook.

Hi, yes I have the exact same issue. The only solution I have is to pull out the power cable and plug it in again.

I've disabled all the energy saving features in case that was the issue but still get the hang.

Have you found any solution?

Yes I have had the same problem (on the same monitor) but rarely. If it happens I do what you've done and unplugged everything and started again.

My issue is more that it just disconnects infrequently, and I have to keep the monitor plugged in, and then restart my mac in order to reconnect it (just unplugging and re-plugging it in doesn't work)

Hope that's helpful

I have tried this afternoon to register my monitor with LG so I can start a support request about the hanging issue.

Unfortunately the monitor doesn't even appear in their support index on their UK website!

Will report back once I've been able to speak to them.

There's been 13 pages of issues going back almost 4 months and, unfortunately, there's not a clear path to resolution.

I wonder how many companies are holding back deploying 12" MacBooks due to this issue. At our company, I'm the single person testing the 12" MacBook and have the issue. We have 350 employees using Windows and the approval has been made for Surface products. Unfortunately, I can't recommend the MacBooks due to the issue until this issue is resolved (or at least acknowledged).

Hi kenofstephen, I don't think that my LG 27UD88 freeze ... I am "only" facing the same two problems harry.jones described:

1) 'No signal' message on the monitor when connecting the MacBook and

2) Crashes / kernel panics when connecting the monitor (which cause the MacBook display and of course the monitor display to go black and require holding down the power button to restart the MacBook)

with macOS Sierra 10.12.1. A MacBook restart will most of the time "solve" both problems until I disconnect and reconnect the MacBook to the monitor.