LG 5K Ultra K not display but charging working

I'm having the same issue. I get display output with my MacBook Pro 16inch (2019) running macOS Ventura but not my or anyone else's apple silicon MacBook pros running sequoia. I've tried various thunderbolt 3 and 4 cables that are the official ones without any luck. Any updates on how to fix this?

For displays above 4K, you need more than USB-C cables and the speed that comes from them.

These genuine ThunderBolt cables are limited to 0.5 meters maximum, for error-free connection to a higher-than-4K display. On a modern Mac, any errors can cause the display to drop out.

ThunderBolt 5 cables are not substantially different, and can only provide higher speeds when ALL devices are actual ThunderBolt-5 devices. When used with ThunderBolt 3, or 4 equipment, Thunderbolt-5 cables act as the older versions -- not better in any way -- and NOT exempt from 0.5 meter maximum length.

The only exception to the 0.5 meter length requirement is for ACTIVE ThunderBolt cables. These tend to cost more than US$129 each, because they contain either strong signal re-drivers, or convert to fiber-optic and back, or Both.

I was using the 0.5m OWC Thunderbolt 4 cable with no luck on any MacBook Pro running macOS sequoia or above. Then I bought an official apple 1m thunderbolt 5 cable and still have no luck. The OWC Thunderbolt 4 cable does work on my 16inch MacBook Pro running macOS Ventura though. Any thoughts?

The 0.5 meter thunderbolt cable should work.

The Mac does not rely on Windows-like side-loaded "Drivers" which are actually packages of resolutions and settings for a specific display. Instead, it goes straight to the immutable source -- it asks the display itself.

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. "No signal detected" is generated by the DISPLAY, not by the Mac.

This query is only sent at certain times:

• at startup

• at wake from sleep — so momentarily sleeping and waking your Mac may work

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

• hold the Option key while you click on the (Detect Display) button that will appear in Displays preferences (from another display)

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

Strange. I have a Mac Mini running 15.6 and no issue with my LG 27" 5K monitor. Just be sure your cable is connected to the first USB port (to the right as viewed from the rear) on the monitor and not one of the others.

as a last resort, For MacOS 12 Monetary and some later versions, some users got relief by deleting some preferences files, then Restarting:

Library/Preferences/com.apple.windowserver

~/Library/Preferences/com.apple.windowserver.<UUID>.plist -OR-

~/Library/Preferences/ByHost/com.apple.windowserver.<UUID>.plist

-- where [~] tilde is an active abbreviation for "current user"

-- and <UUID> is a string of hexadecimal numbers unique to your system, grouped as 8-4-4-4-8 hexadecimal digits

Restart REQUIRED after these deletions.

What Thunderbolt cables do you have..?

macOS upgrade have been known to render long cheap Thunderbolt cables useless.

Test a short 1m Apple Thunderbolt 4 or 5 Pro cable.

apple thunderbolt cable 1m

my external display is also not detecting mac I have m2 pro

have anyone got any solution for this

Please start a new question that includes more details about your Mac and external display,

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