MacBook Pro - not showing display on LG monitor.

to get a Mac display to become active, you need the Mac to query the display, and the display to answer with its name and capabilities. Otherwise, the display will not be shown as present, and no data will be sent to the display.

This query is only sent at certain times:

• at startup

• at wake from sleep

• at insertion of the Mac-end of the display-cable, provided everything on that cable is ready-to-go

• on invoking Option-(Detect Display) button in Displays preferences (from another display)

so try doing some of those things and see if the display comes alive.

Modern Displays with multiple ports are sometimes busy scanning the other ports, looking for an input, and miss the query from the Mac. They need to pay attention to the port you are actually using, or they will miss the query.

Some displays have On-Screen Display settings that can be used to tell the display a computer is attached on a certain port, or a certain port should be highest priority. Changing those may make your display more responsive.

Some displays include their own private "sleep" settings for the display alone. This can allow the display to enter its own sleep mode, on top of the Mac's not sending it data. A display that is sleeping on its own cannot respond to the Mac's query, and will stay dark.

Hello

I bought a LG 24MD4K monitor only had working for 2 hours and it done that would not come on. Phoned emailed LG is the screen cracked, dropped all the usual, send it back to us and we will repair no I said no we don't do that.

Contacted apple send it back send a replacement did that.

Yes and this LG monitor does not wake up the right lead USB-C is connected also I can put my screen password in numerous times does not work then it will work.

Any Help

or do I take it all to apple shop let them look.

Hello M_fergg

yes done it tonight then went to reboot like asking me to put all my details in. ave you tried apple will try them Saturday see what they say.

It is a Nuisance I paid £1300 for Mac mini + £625 for my Monitor.

Vertical artifacts are most likely to be problems with the display itself.

The screen buffer is stored internally as a list or horizontal rows of pixels, which are then "stacked" onto the display to make "the big picture". Software problems or transmission problems tend to show themselves as horizontal stripe anomalies.

The cord is white, which suggests it might be the USB-C charging cord that came with your Mac. If so, that’s not going to work – that cord carries power only, not data.

A standard USB-C cable will work.

E.g., https://www.amazon.com/Cable-Matters-Monitor-Resolution-Delivery/dp/B07X31FG6Z/

Hello

Looked it up on apple website ( if your Mac starts up with a blank screen) what to do'

The LG 24MD4K Mac done work with LG for this monitor.

The monitor has no on/off button as you say the screen detects that some one is getting in touch screen opens, if somewhere in the software/hardware not (computer person) the message not getting interpreted correctly no joy.

But I bought switched on updates then went dead you can't access that information unless you have another way of getting online.

If keyless card entry is not reconised when standing by car you don't get in

Hello Grant Bennet-Alder

thank you for your information is contacted Apple I was told they would repair the monitor. It is less than a month since it was purchased.