Monitor resolution issue on Tahoe 26.2

Question

Level 1

4 points

Monitor resolution issue on Tahoe 26.2

My MacBook Pro updated to 26.2 overnight, and suddenly my external 24-inch recommended monitor resolution has disappeared from the available resolutions list. (the recommended resolution is 3840 x 2160 @ 60 Hz)

Also the monitor type itself has changed on my monitor list. Mine is an LG 24UD58, but it has been changed to "DP2HDMI 17602" and I don't even have one of those.

It was working perfectly yesterday, but now even at the highest resolution the monitor is fuzzy and hard to read. Help!

MacBook Pro 16″, macOS 26.2

Posted on Jan 7, 2026 1:50 PM

Reply

Answer 1

Top-ranking reply

neuroanatomist

Level 9

56,109 points

Jan 7, 2026 2:46 PM in response to jtomalley

macOS has become progressively less tolerant of video data packet loss due to sub-par cables. There have been several reports of setups that worked in Sequoia not working in Tahoe, with nothing changed but macOS. Usually they just stop working, first time I’ve seen a 4K display showing as HD.

I presume you’ve tried disconnecting/reconnecting the display and rebooting the Mac.

Best recommendation at this point is to try a new cable. Be sure to use high quality cables – HDMI should be labeled Ultra or Premium.

Reply

Answer 2

Barney-15E

Level 10

122,210 points

Jan 7, 2026 5:46 PM in response to jtomalley

jtomalley wrote:

I have four Thunderbolt/USB-C ports. No Displayport or USB-A.

The USB-C port is both Thunderbolt video/data and DisplayPort, along with whatever USB spec.

The cable is a straight HDMI to Thunderbolt 6' cable with no adapters.

So, the cable states that it is a Thunderbolt video to HDMI? If it is, it is not identifying as such. Your Mac sees it as a DisplayPort to HDMI and at a low spec.

Reply

Answer 3

jtomalley Author

Level 1

4 points

Jan 7, 2026 4:27 PM in response to neuroanatomist

The cable IS labeled as Ultra HD... and yesterday I was at OS 26.1 and it was working fine.

I disconnected / reconnected the display and rebooted my MacBook first. No help there. I will order and try a new cable and in the meantime I will deal with the fuzzy picture. I use it for work and absolutely need the extra monitor.

Reply

Answer 4

Barney-15E

Level 10

122,210 points

Jan 7, 2026 4:44 PM in response to jtomalley

What port are you connecting to the monitor? I don't know, but it seems to be saying you have some DisplayPort to HDMI adaptor, or maybe it just thinks it is.

Reply

Answer 5

jtomalley Author

Level 1

4 points

Jan 7, 2026 5:00 PM in response to Barney-15E

I have four Thunderbolt/USB-C ports. No Displayport or USB-A.

The cable is a straight HDMI to Thunderbolt 6' cable with no adapters.

Reply

Answer 6

jtomalley Author

Level 1

4 points

Jan 8, 2026 12:30 PM in response to jtomalley

UPDATE - when I logged into my MacBook Pro this morning for work, it was back and configured correctly. I didn't change anything. Same cable, same Mac, same monitor. It's fine now.

???

Reply