Level 1

43 points

External monitor flickering Macbook 2016

I have a Macbook 2016 and both an Apple USB-C to Multi AV-HDMI adapter and a LogiLink USB-C to DisplayPort adpater.

I'm trying to use a Dell 3008WFP monitor as an external screen (maximum resolution 2560x1600 @60Hz) with my MacBook, but that doesn't seem to work well.

The monitor often goes blank after a short time ("power-saving" mode) or only occasionally displays an image and then goes blank again. Using a LogiLink USB-C to Displayport is a bit more stable then the Apple adapter, but also often experiences the same problem.

On a smaller Samsung 1920x1080 monitor the Apple Multi AV adapter seems to work perfectly fine, but on the Dell it isn't stable (using HDMI at 1920x1200 resolution, as the Dell only supports higher resolutions over DVI or DisplayPort).

The adapter is updated to the latest 2.33 firmware. Is there a problem with my (just new) MacBook? Or is this a software issue? Is there a work around? Anybody have a good experience with the MacBook at 2560x1600@60Hz on an external screen?

Posted on Jul 22, 2016 6:07 AM

Top-ranking reply

garygomm

Level 1

5 points

Posted on Dec 11, 2017 9:59 AM

So...I bought a MacBook Pro 13" (2017) with Touch Bar. I have a 34" curved LG Ultra Wide at home and a 28" Samsung Ultra Wide at work. At home everything worked perfectly - no flickering when the external monitor was plugged in. Get to work on Monday - hey presto - Flickering! hence me doing some searching and finding this thread.

Monitor Specs:

LG Monitor 34": 2560x1080

Samsung Monitor 28" : 3840x2160

LG Monitor at home, connected via HDMI and HDMI port 1 on monitor - no issues. Monitor defaulted to its standard resolution when plugged in with the Apple Multi AV adapter.

Samsung monitor at work : connected via HDMI and HDMI port 1 on monitor - ISSUES. flickering every few seconds and every minute or so white screen - just for 1/4 second but enough to drive crazy.

The Samsung seemed to be in right resolution as when tried using the scaled resolution the monitor popped up and said it was adjusting - but still flickered.

I've then moved the cable to plug into HDMI port 2 on the monitor - hey presto - flickering gone! Also immediately I plugged into HDMI port 2 on the monitor the picture/text on the Samsung was very much smaller seeming to indicate the monitor had changed resolution - i.e. at the default resolution for the monitor. When I plugged to the HDMI back into the HDMI port 1 the screen resolution on the monitor went back to its bigger text size and started flickering again. When plugged back into HDMI port 2 - resolution changes and flickering stops.

This seems to indicate that there is something going on between port 1 and port 2 on the monitor. Nothing to do with the MacBook it would seem. The monitor should contain an EDID file which the matchbook reads when the monitor is plugged in which tells the MacBook what resolutions are available and what the default is. For some reason there is a difference between HDMI port 1 and HDMI port 2. I know that HDMI ports on TV sets can be different and some devices will not output their signal when plugged into HDMI 1, but will on HDMI 3 - this due to slightly different configurations on the ports. The TVs also have an EDID file which should be read to see what resolutions etc.

The good news is this seems to indicate it is not hardware, but a driver/config issue. Bad news is we now watch the Monitor manufacturers says it is an Apple issue and Apple say it is monitor issue - leaving us stuck in the middle.

I was using SwitchResX on my 2013 MacBook which worked perfectly on both monitors - using HDMI and into HDMI port 1 on both monitors.

The monitor is flickering because it is not getting correct info in the signal. I would suggest trying the other ports on the monitor or TV per above or trying SwitchResX. I have not tried SwitchResX on the new MacBook - I'll only install it if the issue comes back on HDMI port 2.

This looks like it is something to do with resolutions and refresh rates and depending on the monitor you may be ok or not. On my previous MacBook I installed SwitchResX because the monitor I had before I had the LG 34" used to give a fuzzy picture until installed. I jut never uninstalled it when I got the 34".

Hope this helps narrow down the issues for some of you.

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24 replies

wenchenx

Level 1

4 points

Aug 13, 2016 10:07 PM in response to Schendstok

I have the same issue.

It might be radio frequency interference problem between USB 3.0 and 2.4Ghz Wifi.

So, I'm turned off my wifi and using usb RJ45 ethernet. It doesn't flickering anymore.

jdeath

Level 1

17 points

Aug 17, 2016 8:00 AM in response to Schendstok

My coworker and I recently purchased 2016 MacBooks to use for work, and external monitors and docks to go with them. We both experienced this major, unacknowledged issue- but thought it might be related to the monitors or docks rather than the MacBooks. However once I got home, using a different monitor and the official Apple multiport adapter I have the same result.

Another symptom I experienced was a prompt to install a USB-C update almost every time I plugged in the adapter or dock. It didn't seem like the update ever properly installed.

Usually I reboot, and this makes the problem disappear (also pointed out by user tom-ch). Hopefully somebody inside Apple realizes this is an issue and gets us some steps to rectify it- other than rebooting our machines every day (like cave men! 😉)

Sep 23, 2016 9:39 AM in response to Schendstok

I'm also experiencing this issue with the 2016 macbook. I facilitate meetings in four different conference rooms every day each with different tv monitors I use a external displays. Each monitor experiences a different issue (flickering, not working at all, intermittent blank display). I have tried the Apple multi-adapter and a CableCreation USB-C to HDMI adapter but both have issues. This is definitely something hardware or software related for the computer. I'm hoping a USB-C update will eventually resolve this.

Sep 23, 2016 10:12 AM in response to Schendstok

Hi Schendstok & Darren (specialist),

Please take a look at our discussion of the same problem which many of us are experiencing:

Macbook 2016 HDMI output flickering

Regards,

Ken

jdeath

Level 1

17 points

Nov 21, 2016 10:24 AM in response to darren.s

Diagnostics show nothing abnormal- this is a hardware or software issue with the new MacBooks in general. Mine has it, my spouse's has it, my coworker's has it. Others in this thread have this issue as well. I honestly can't say I've ever seen a MacBook without this problem. It is a very serious issue which affects my productivity every single day, and it warrants a real response from Apple.

Nov 21, 2016 4:01 PM in response to Schendstok

I have a similar problem with my MacBook Pro with toucher 13 inch late 2016 (just got it) constant flickering every with a samsung 28 inch 4k monitor using - genuine Apple Multiport adaptor and HDMI. I updated the software for the Mulitport Adaptor and tried both left and right USBC ports. Monitor is running at 30Hz

Hoping someone may know what the issue is or provide inside as to a monitor that will not have these issues.

supraru

Level 1

8 points

Nov 22, 2016 7:51 AM in response to Schendstok

So, I hope this is helpful, my apologies if not. But I had the same problem with identical symptoms using the same adapter only with a Samsung 4K monitor. My resolution? I was using a pre HDMI 2.0 cable. Swapped to a HDMI cable built in 2014 to the new spec. Issue solved.

I know not all the monitors in question in this thread are 4K, but I figured with so many old HDMI cables floating around out there that weren't built to work with more recent displays, it's worth a shot. Often I don't even think of troubleshooting the simplest part of the equation, first.

Feb 6, 2017 11:26 PM in response to andrer9999

It doesn't work for my case, Hootoo is the worst in fact.

I contacted their support, they said they would give me $15 refund but never send me the $.

beacive

Level 1

8 points

Jul 21, 2017 8:57 PM in response to Obsthedog

I have the same issue with the Samsung U28E510. It's running in 4K but only 30 Hz and blacks out periodically. I don't have a solution and need one.

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External monitor flickering Macbook 2016