U4025QW, MacBook Pro, constantly disconnects

Question

I am experiencing frequent disconnects when using a Dell U4025QW with a MacBook Pro (Nov 2024 with Apple M4 Max). These disconnects happen as often as a dozen times a minute or as little as few times a day. These disconnects lead to an immediate logging out of MacOS. This does not occur at all with my much older MacBook Pro (2017 Intel model). I am connecting the U4025W via an Apple Thunderbolt 5 cable, which I have further insulated with snap-on ferrite cores. Display and MacBook Pro are all on the latest firmware/OS versions.

I believe there is interference from BlueTooth devices (perhaps from my keyboard and mouse) causing these disconnects, but I am at a loss as to why they only happen with this specific configuration.

Could this be a faulty display? I have seen other reports of Mac users with this issue but have not found a specific solution. Any help would be greatly appreciated.

sirgromit39f9dc · Accepted Answer

At the suggestion of a poster on Reddit, I switched to a Thunderbolt 3 cable and can confirm I've now gone several days without a single disconnect. I haven't had significant extended use yet, but I'm comfortable enough to think that this has fixed it! There appears to be some kind of compatibility issues with this display (which is Thunderbolt 4) and M4 Macs (with Thunderbolt 5). Using a Thunderbolt 3 cable would knock it down to Thunderbolt 3 specifications but my understanding is that there shouldn't be too much of a difference performance or functionality-wise with M4 Macs and this display running at Thunderbolt 3 specs. I hope this helps someone in the future.

drgarson · Accepted Answer

Resolved without any cable change by plugging in the MacBook charger prior to connecting TB4 or TB5 cable to the monitor. It is related to charging power draw, it seems.

DELL-ChrisM2 · Answer

Please verify =

- Using the provided U4025QW 1.5 M Thunderbolt 4 Active cable had the disconnect issue
- Using unknown length Apple Thunderbolt 5 cable had the disconnect issue
- Using unknown length/manufacturer Thunderbolt 3 cable did NOT have the disconnect issue

sirgromit39f9dc · Answer

@DELL-ChrisM2​  - Using the provided U4025QW 1.5 M Thunderbolt 4 Active cable had the disconnect issue This is correct. I had the disconnect issue using the included Thunderbolt 4 cable. - Using unknown length Apple Thunderbolt 5 cable had the disconnect issue This was the Apple Thunderbolt 5 (USB‑C) Pro Cable (1 m) and it had the disconnect issue. - Using unknown length/manufacturer Thunderbolt 3 cable did NOT have the disconnect issue. I have not had the disconnect issue since switching to the Belkin Thunderbolt 3 USB Type-C Male Cable (3', Black) cable.

sirgromit39f9dc · Answer

I would also like to point out that I did not have this issue until I switched my computer from a 2017 MacBook Pro (which only supported Thunderbolt 3), to the current 2024 model (which supports Thunderbolt 5). The older MBP worked with the included Thunderbolt 4 cable.

user_af3dcd · Answer

I have exactly the same issue.

U4025QW is constantly disconnecting with:

- original 1.5 M Thunderbolt 4 Active cable (provided with monitor)

- Apple 1 M Thunderbolt 5 Pro cable

Issue is not happening when I use:

- Thunderbolt 3 cable.

I do have Macbook Pro M4 Max.

Is there any coming fix for this @DELL-ChrisM2? I don't think using TB3 cable is real solution to this, then we are bottlenecked and we cannot use full potential of this monitor.

Thank you!

DELL-ChrisM2 · Answer

For us to escalate this issue to displays team we need at least 10 users to post that they all have the same issues using same computer and U4025QW.

sirgromit39f9dc MacBook Pro M4 Max
user_af3dcd MacBook Pro M4 Max
flux42 MacBook Pro M4 Max
drgarson MacBook Pro M4 Max
Ninthiend0 MacBook Pro M2 Pro

flux42 · Answer

@DELL-ChrisM2​ I have the same problem: MacBook Pro M4 Max 16-inch

drgarson · Answer

@DELL-ChrisM2​ I also am experiencing the same issue both with the provided TB4 cable and at TB5 cable. I have not yet tried the TB3 issue but if that resolves the issue, I hope that Dell will still recognize this as an issue needing resolution since the cable included does not work with the device purchased and TB3 has significantly lower bandwidth. I’m on a M4 Max MacBook but I don’t recall the issue on my M2 Max

marinabyte · Answer

Hi @DELL-ChrisM2 ,

I’m experiencing the same issue with my U4025QW connected to a MacBook Pro M4 Max on the latest macOS Sequoia and Tahoe releases. Every 30 minutes to a few hours, the Dell briefly goes black for a few seconds while the Mac and peripherals keep working normally. It’s been happening across firmware versions (I’m currently on M3T104) and with multiple certified Thunderbolt 4 cables.

This isn’t an isolated case. Several other users on Reddit are reporting identical behavior:

https://old.reddit.com/r/Dell/comments/1dqrss8/u4025qw_monitor_randomly_shuts_off_macbook_pro_m3/
https://old.reddit.com/r/Dell/comments/1npkf1q/u4025qw_shuts_off_randomly_for_a_few_seconds/
https://old.reddit.com/r/Dell/comments/1jz9kr8/u4025qw_random_disconnects_anyone_find_a_good/

Dell’s UltraSharp line has an excellent reputation, and it would be a shame to see that undermined. Please escalate this to the display team. Many professional Mac users are affected, even if not everyone is posting here. The Reddit threads should help illustrate how widespread it is.

Thank you!

user_af3dcd · Answer

@drgarson​ Sadly, for me this is not true. I tested with charger connected to MacBook and issue is still there.

marinabyte · Answer

Hey @user_af3dcd

Using the MacBook charger didn’t fix it for me either (even when I plugged in the charger first, then the monitor).

However, I followed a suggestion from a reddit thread and disconnected the monitor from power completely overnight and surprisingly, that completely resolved the disconnect issue for me (at least for now), even using just the tb4 cable that came with the monitor. So if anyone’s still seeing random dropouts even after trying different cables or power sequences, it might be worth giving that a shot.

Ninthiend0 · Answer

@DELL-ChrisM2​ Add me to that list please. Been having this issue since i purchased the monitor. Running on a Macbook Pro M2 Pro

sirgromit39f9dc · Answer

My very preliminary testing of the recently released M3T105 firmware seems to have fixed the disconnection issue we have been having. I have been using the display with the included Dell Thunderbolt 4 cable and my 2024 M4 MacBook Pro without any issues for a limited time, but long enough that previously I would have almost certainly experienced the issue.

Unfortunately, the installer for this firmware version does not seem to work on the latest macOS version(s) and I had to resort to using my old Intel MBP to update the firmware. If any one else can update to the new firmware and test, that would be great. The latest firmware is available here: https://www.dell.com/support/home/en-us/drivers/driversdetails?driverid=r7c3k&oscode=mac1&productcode=u4025qw-monitor

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U4025QW, MacBook Pro, constantly disconnects

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