Macbook Pro 13 (2020) M1 and LG ultrafine 5k monitor

I have a new MBP M1 and Ultrafine 5k. It does NOT support 5k resolution. The max resolution is 3840 X 2160 (if you option-click scaled, you can see all the supported resolutions and this is the largest).

Not sure who is writing specs, but 3840 is the max you can do.

No the Macbook Pro 13 (2020) M1 does not work any 5K monitor that I have tried, such as LG's "UltraWide 34WK95U 34-inch Monitor- 5K2K 21:9 UHD 5120x2160 Nano IPS, VESA DisplayHDR 600, Thunderbolt" (recommended by Apple for previous Macs).

It syncs at a lower resolution. However this appears to be an Apple Bug as when you scale the resolution from system preferences it changed to a higher resolution, but still not the full 5K.

Anyone saying it does is quoting Apple's specs, but has probably not tried it themselves.

It does work with two 6k monitors I have access to.

Tested using Big Sur 11.0.1 - Dec 8, 2020 - Hopefully Apple will fix this quickly.

Yes, as of 2021-01-01, the last option (when you press the Option key and select "Scaled) is 5120 x 2880 and the one before that is "2880 x 1620." There is not option for "3440 x 1440--at least not yet.

Yes. The M1 Mac notebooks support up to a 6K display.

Yes, it is fully running and loading via USB-C - video and audio. Of course at 4K instead.

I just bought an M1 Macbook Air (Big Sur 11.1), I can confirm that it does NOT fully support LG 5K2K display. In general it works but the problem is that you cannot scale it to be as 3440x1440, instead, for the last option of 'More space', you can only scale it to 5120x2160, which the text is TOO SMALL to use. I consider this as a bug. Hope Apple to fix it soon.

I have had a 13" M1 MacBook Air for about 24 hours (as of 2020-12-22.) Initially, the 27" LG UltraFine 5K monitor connected, although the display did not appear to resolve to 5K. Then after using it for a few hours it powered off and it could not be awakened. The monitor is receiving power because it is powering the M1 MacBook Air. After trying all reasonable checks (connecting and disconnecting the monitor, using a different Thunderbolt/USB-4 cable, rebooting the computer with the monitor connected and the monitor disconnected), I could not get the monitor to display again. I contacted Apple support and after one-tech vanished with no attempt to reconnect, learned that Apple Engineering is working on a "known issue", but has identified no timeline for resolution. I have been promised an update by midday (MST) on Thursday, 12/24/20.

No definitive resolution at this point. It seemed like the problem had "vanished" as of 2020-12-24. And via the tech briefing that Apple offers new customers I was able to figure out how to get to the maximum resolution available on the LG UltraFine 5K monitor (you have to go to System Preferences in the Apple menu, select Displays, then on the LG UltraFine box that comes up make sure "Display" is highlighted, then de-select "Scaled" and then, while holding the "Option" key on the keyboard, re-select "Scaled" and you will see a variety of resolution choices rather than just the four that you normally see.) That was the good news. The bad news was that on 2020-12-26, the LG monitor screen again went blank. This involved another series of encounters with Apple Tech Support, ultimately leading to a session with a senior adviser with whom I worked to upload a diagnostic file. That took about an hour. As of 2020-12-30, I had hear nothing further, went through the Apple Tech Support hierarchy again and finally got connected to a senior adviser who found that Apple Engineering had concluded that could not read the diagnostic file that was uploaded. He had no explanation as to why I had not been notified. So, I went through another extended effort to upload a diagnostic file and am waiting for further response. Meanwhile, I think I may have found a work around which involves setting the monitor to never "go-to-sleep" And, so far (as of 2021-01-01) that has solved the problem. I am able to shut down my MacBook Air for the evening and then boot it up in the morning and the LG UltraFine5K monitor turns on fine--so far. To set the display to not go to sleep is a bit tricky if you have just migrated to the Big Sur OS. This is because "Energy Saver" not longer exists and you have to click on "Battery", then you select "Power Adapter" and move the slider under "Turn display off after", all the way to the right. Of course, you then get the message that says "Never letting your display go to sleep may shorten its life." I address this simply by shutting the M1 MacBook Air down when I'm not using it. So, still waiting for more definitive feedback from Apple Tech Support, but at least the external monitor is not longer randomly shutting down--at least for now.

Well after some updates of LG and Macbook the monitor wakening and black freeze problem gone. Only lasting problem is when it wakes sometimes it changes resolution and could shift the main monitor to other one. But u could correct it with repluging the thunderbolt of display again.

Agreed - the specs say it should, but I have no personal experience with an M1 Mac. I have that exact monitor (well, the business version of it, but they’re identical), and it works fine with my two 16” MBPs (Intel, obviously).

I will point out that simply clicking on the Scaled radio button with the graphical selection options does not enable me to get the full 5120x2160. For that, you need to hold the option key when you click the Scaled button to see the list of all supported resolutions. Have you tried that?

Just to add, Apple update 11.1 changes the symptoms. Now the monitor is not detected after the the computer goes to sleep. By unplugging and re-inserting the Thunderbolt connector repeatedly, the monitor will normally wake up eventually or occasionally crash them Mac.

Power cycling the computer always restores monitor detection. (Same for BENQ and DELL 5K monitors - this is not a monitor issue).

On my LG, monitor (not yet tested on other monitors) - checking the HDR option within the display system preferences makes additional resolutions appear (with the Option Key held down when clicking the Scaled radio button) - but beware, some options crash the computer and others do not generate a display.  If HDR is checked the MAC outputs in 5k however scaling options that work are limited.

M1 Macbook Pro 5K support seems flaky and buggy. (5K works better on a friends Mackbook Air using the same monitor!)

As of 2021-01-06, I received no response from Apple Engineering on the display resolution or intermittent power interruption issues. So, I gave up. on resolving the gap in available display resolution on the LG 27" UltraFine 5K monitor. The problem was that there is no display scale option for the 5K monitor in between the maximum of 5120 x 2880 and 2880 x 1620. Anticipating that Apple Engineering would be non responsive, I ordered the smaller LG 24" UltraFine 4K monitor. It offers a maximum resolution of 3840 X 2160 and has several other resolutions (such as 3008 x 1692 and 2560 x 1440) that make for reasonable display of applications. While this smaller 4K monitor has no camera, that is not an issue for me because I already have an external high-definition wide angle camera that I use for Zoom and other video meeting applications. It also has the advantage of being much less expensive--about $700 for the 4K monitor vs $1,300 (US) for the 5K monitor.

After two additional attempts (on 2021-01-02 and 2021-01-05), I was unable to obtain an update from Apple Engineering on the gap in scaled resolutions available for the 27" LG UltraFine 5K monitor. So, I gave up and ordered the 24" LG UltraFine 4K monitor. While I would like to have a larger monitor, the range of scaled display resolutions available on the smaller one is finer-grained and more workable--topping out at 3840 x 2160 and stepping down to 3008 x 1692, then 2560 x 1440, and so on. Accordingly, I sent the larger monitor. back to Apple. While the smaller monitor has no camera, this is not an issue for me as I use an external high-definition camera for Zoom and MS Teams sessions. The smaller monitor is also less expensive--$700 (US) at the online Apple Store for the 24" 4K monitor vs $1,300 for the 27" 5K monitor. And, for the kind of work that I do, the quality of images on the screen of the 4K monitor looks just as good as they did on the 5K unit.

Good tip, I didn't know about the option key, but in my case it didn't show any higher resolutions, just lower.

The chosen scaled resolution outputs that resolution to the monitor for it to up-scale the video to its native size, which it does, but the display default option only outputs 3440 x 1440 where the scaled option allows up to 3840 x 2160.

(The system information page shows the monitor as 3440 x 1440).

This is the same on 2 other makes of 5k monitor. So it's unlikely to be an LG problem.

Do you have an update? I'm ready to return both, Macbook Air M1 the LG 34WK95U. :(