Unable to detect external monitor after macOS Ventura 13.1 update

Question

After update macOS from Ventura 13.0 to 13.1 my Macbook Air (M1, late 2020) does not detect my external monitor connected with Type-C (LG 35WN75C-B)

It was working right before the update.

I've tried to:

Restart system
Plug off monitor, restart system, and plug it on again
Press "Detect Displays" button after all those actions.
Change monitor Display port version from 1.4 to 1.2 (and reboot system again)
Power off monitor and turn it on again after system restart as described in this question

Any ideas how to fix it?

Update: After switching USB-C Cable to Apple's original one my Macbook now able to recharge battery from monitor, but still doesn't see it.

I forgot to ask why you downgraded your monitor’s firmware — Allan, Jan 12 '23 at 05:44
@Allan I've seen this topic on MacRumors and thought that it might help. Anyway I've changed it back to v1.4 — Yaro, Jan 12 '23 at 05:59
Where exactly, in MacOS Ventura, does one find the "Detect Displays" button? — threed, Apr 05 '23 at 21:59
You Need to hold down the Option key and it supposedly switches the Night Shift... button to Detect Displays but on Monterey it is not working for me. — Nigel Sheridan-Smith, May 08 '23 at 23:20
I worked it out! You need to use the USB-C power, not standard power adapter. Then the Option key works as well. If both are plugged in, the USB-C external display won't work :( — Nigel Sheridan-Smith, May 08 '23 at 23:24

score 4 · Answer 1 · answered Feb 07 '23 at 15:21

4

I've been struggling with this problem for a while, but this worked for me: Turn off monitor. Unplug HDMI cable from USB-C to HDMI adapter. Unplug USB-C to HDMI adapter from Macbook Air. Plug adapter back in to Mac. Restart Macbook. Turn on monitor. Plug HDMI cable into adapter.

I think there's some state hanging around in the HDMI adapter and/or Ventura that needs to be reset.

answered Feb 07 '23 at 15:21

Jud Leonard

41
2

I guess you're right about these observations. I was struggling with the same trouble after upgrading to Ventura 13.2.1. I have two external monitors connected to my Mac and the device stopped detecting both of them after upgrading. – Arun Ramachandran Feb 19 '23 at 22:49
This seems to have solved my problem for me, thanks for saving me from the headache of fiddling around with the HDMI cable... – 92lexus Nov 04 '23 at 16:26

Yaro · Answer 2 · 2023-01-18T10:56:34.137

1

I've resolved it. I have no idea how does it work, but here is what I did:

Connected USB Hub
Plugged USB-C cable into it
Monitor connected
Remove USB Hub
Connected cable directly
Monitor connected again

It's pretty strange behaviour

Update: after I've connected this monitor to my PC I'm unable to connect monitor to Macbook again. So - problem was not resolved

UPDATE 2: Solution that resolved issue:

Completely shut down monitor.
Remove cable
Shut down macbook
Wait for some time (In my case it was about 8 hours)
Plug in cable to macbook
Turn on macbook

This solution described multiple times at different forums. But in my case I had to wait more than 5-10 minutes while my MB is off. And I still have no idea how does it work

edited Jan 18 '23 at 10:56

answered Jan 12 '23 at 06:54

Yaro

131

Was the monitor detected when plugged in the USB Hub before the update? – David Anderson Jan 12 '23 at 07:17
@DavidAnderson It was. But it was a months ago - even before 13.0 update. – Yaro Jan 12 '23 at 07:45

score 1 · Answer 3 · answered Jan 16 '23 at 23:03

I’ve been battling with the same problem and after reading posts about this issue I believe it’s MacOS Ventura’s fault. No solutions I found helped so I’ll try to downgrade my macOS as a last resort.

Check out this detailed thread: Upgrade from BigSur to Ventura macbook pro not detecting external monitors and TVs

score 1 · Answer 4 · answered May 08 '23 at 23:26

1

Use USB-C power only.

If you plug in another power adapter (e.g. MagSafe) then it disables some of the functionality of the USB-C port. This includes disabling the Option key for Detect Displays on the Display settings page in System Preferences.

answered May 08 '23 at 23:26

Nigel Sheridan-Smith

111

Ok, so you are saying that if the laptop is getting power only from USB C, Detect Displays will be accessible via the Option key, right?. But if power is coming from MagSafe (or whatever other non-USB source), then Detect Displays will not be available. This seems like an odd choice on Apple's part: why can't I connect my charger and an external display? – Paul Jul 28 '23 at 21:17
Most USB-C monitors will power the laptop as well, so the MagSafe is unnecessary. It does seem an odd choice that you can't config it when both are plugged in at the same time. – Nigel Sheridan-Smith Jul 30 '23 at 03:16

Allan · Answer 5 · 2023-02-14T16:03:29.360

Your monitor should support USB-C without having to go through that "dance" shutting down, disconnecting, waiting, and reconnecting. Per the specs page on LG's website:

INPUT		OUTPUT
HDMI	Yes x 2	DisplayPort	Yes x 1
USB Type-C	Yes	Headphone Out	Yes
USB-C (DP Alternate Mode)	Yes	USB-C (Data Transmission)	Yes
USB Down-stream	Yes x 2

Below are some items you want to check. I can't tell you how many times (from extensive professional experience) replacing a simple cable fixed troublesome issues. It's always good to start with quality connections.

Get a USB-C cable that supports DisplayPort Alt Mode.
Try a USB-C to DisplayPort cable and connect to the DisplayPort interface (not USB-C Alt). In my experience, DisplayPort has always been a reliable technology.
Ensure you're running the latest firmware of your monitor. LG Software Downloads.
Verify this problem doesn't exist on a different computer (like a Dell laptop). If it does, then this is definitely a monitor issue and not macOS. This will help you focus your efforts going forward.

When purchasing cables/adapters, always go for reputable brands like StarTech, Cable Matters, Belkin, Cable2Go, Pluggable, etc. They cost more, but their quality is much higher than the no-name discount brands. Many times you may purchase what seems like a decent cable, but to save costs, they remove support for certain features.

Despite all the capabilities ... it is important to note that not all USB-C products support USB-C’s full functions.

^{Source: BenQ USB-C FAQ}

Hopefully this will get you working or at least pointed in the right direction of a solution.

score 0 · Answer 6 · edited Nov 02 '23 at 16:36

I'm using a Lenovo USB-C Dock (Gen2) and a few weeks ago my 2020 MBP13 wouldn't recognise the attached 34" Samsung Display. Whilst attaching a 2018 ThinkPad (running Fedora 38) just recognised the Display as expected...

Just now I realized that I also had an issue with charging from that Dock a while ago before it started to refuse to recognise the display!

As I read all those suggestions of attaching USB-Hubs and so on I attached my USB-C charger before I connected the docking cable and bada boom the display gets recognised again!

So attaching other USB stuff to get it to trigger the display recognition definitely works!!!

score -1 · Answer 7 · answered Jan 12 '23 at 09:21

-1

I came across an article on how to fix macOS Ventura/Monterey not detecting external monitor.

Apart from the method you have taken, it also recommends that you do the following:

Allow Accessories to connect to USB-C connections.
Boot into Safe Mode.
Update the hub driver or software.
Change screen resolution.
Update your Mac.
Disable 'Automatic graphics switching'.
Downgrade macOS

Maybe you can try one of them to get your issue resolved.

answered Jan 12 '23 at 09:21

TCJunckie

1

This is basically the list the topics covered in the linked page, how does this relate to the specific problem described in the question? – nohillside Feb 07 '23 at 15:59

Unable to detect external monitor after macOS Ventura 13.1 update

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