MacBook Pro M3 (2023, 16") Wifi problem with HDMI

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Level 1

7 points

MacBook Pro M3 (2023, 16") Wifi problem with HDMI

I got this machine a month ago and noticed that whenever I had connected my machine to my LG C3 (42") using the HDMI port, I would stay connected to the WiFi but no traffic was actually going through.

This would happen either initially, or sporadically as I was using, but it was happening.

I took it to my local Apple store and they gave me a new machine, and the same issue was happening. I was wondering if other people were facing this issue, specifically losing internet (while WiFi stays connected) when using the HDMI port. I heard people saying using a usb C - HDMI dongle will help but this is an expensive piece of machine and I expect it to work.

I thought perhaps it could be the monitor causing interference as it also had an option to connect to the internet, but I disabled that and the issue persists still.

Some things I can rule out:

WiFi Problem

I have a Macbook Pro M1 for remote work and it's never had an issue.
I tried using my mobile data hotspot but the same issue happens.
I tried switching locations of M1 and M3 (it's literally 3 feet apart) and still the same problem.

HDMI Cable Problem

I tried using the dongle, and it works fine. I also tried using the cable for the Macbook M1 Pro and there's no problem.
In any case, this is the cable I'm using (Amazon Canada link)

I don't know if it's a hardware issue, a firmware issue, or a me issue, but I'd like to get to the bottom of this. Hopefully this community can help or hopefully this can be noted by the folks at Apple.

It happens very sporadically so it's hard to capture but I have it on video when it did happen.

MacBook Pro 16″, macOS 14.4

Posted on Apr 7, 2024 02:27 PM

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Answer 1

Top-ranking reply

ke_liz

Level 1

14 points

Aug 16, 2024 08:25 AM in response to kebn

Same issue, solved by getting another HDMI cable (the one with metal covered end). It seems like the old cable has some radio interference problem.

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Answer 2

Jul 3, 2024 06:34 PM in response to kebn

Why do I have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer?

Some USB 3 devices can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. Here are some tips to avoid this issue:

• If your USB device has a cable long enough that you can move the device, place it away from your Mac—and make sure not to place it behind your Mac, or near the hinge of its display. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there might interfere with your wireless connections.

• If you're using adapters or dongles on a Mac computer with Thunderbolt 3 (USB-C) ports, plug them into the front port on the left side of your Mac, or into the ports on the right side (if your computer has them). These ports are the farthest away from the antennas, making interference less likely.

• To avoid interference on the 2.4GHz band using Wi-Fi, try using the 5GHz band instead. You can change this on your wireless base station. Bluetooth always uses 2.4GHz, so this alternative isn't available for Bluetooth.

from:

About USB on Mac computers - Apple Support

Resolve Wi-Fi and Bluetooth issues caused by wireless interference

Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

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Answer 3

abovdal

Level 2

389 points

Apr 7, 2024 03:31 PM in response to kebn

This is a shot in the dark, but are you sharing the M3 MBPro's internet connection with the external screen in some way (other than the HDMI)? Or is there a wifi or bluetooth connection between the two? I've had the problem of (unintentionally) trying to connect two devices in two different ways causing problems.

Also, what does Activity Monitor show for network traffic when the two devices are connected?

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Answer 4

kebn Author

Level 1

7 points

Apr 7, 2024 03:37 PM in response to abovdal

I'll have a look at the activity monitor and update you when the problem happens again.

I've turned off WiFI for the external screen and went as far to disable even the ethernet connection on the screen to remove any interference. Only bluetooth connection is keyboard & mouse, but I'll try disabling these too next time a problem happens.

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Answer 5

Mmarduke

Level 1

8 points

Jul 3, 2024 03:22 PM in response to kebn

I had the same issue, was able to solve it by switching to 5GHz wifi signal instead of 2.4. If your router supports 5GHz, you should be able to switch to it in your router settings.

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MacBook Pro M3 (2023, 16") Wifi problem with HDMI

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