How to fix refresh rate Issues on Dell monitors after Sonoma update

Two Thunderbolt displays here with a 13-inch, 2020, Four Thunderbolt 3 port. 14.2 made it even worse. One display just keeps cutting out for no reason. complete nightmare while on a Zoom call. I have peripherals like an audio interface and mic connected to the monitors, and it all worked flawlessly until upgrading to Sonoma. Feeling like Apple is trying to force us to buy their newest monitors, but shelling out over $2K for two monitors just isn't in the budget. To say that I'm angry with Apple would be an understatement.

I have one of their expensive monitors. Its an older LG 24" 4k Ultrafine they sold.

Seeing the various intel, M1, and M2 users and Apple retailed monitors in here.

I would be amused if an M3 + Studio Display owner chimed in here after 17.3

I had a very similar issue.

McBook Pro 14 inch with Apple M1 Pro Chip running Sonoma 14.1.2

My LG UltraWide Monitor dd not have the right resolution (2560x1080).

Every time I disconnected the HDMI cable and re connected it, different options appeared, so I ended up rebooting, disconnecting everything and reconnecting it and it fixed itself.

Same issue here using an AOC 27G2U/BK monitor @ 2018th MBP with latest Sonoma 14.2.1

my workaround (please don’t laugh !!!):

connect the monitor by both HDMI_to_USB-C & Displayport_to_USB-C

via old Satechi USB Hub with HDMI and via old HAMA DP_to_USB-C adapter

Works fine @ 120 Hz when Power_to_USB-C is connected too.

Doesn’t work by disconnecting Power.

Doesn’t work by disconnecting HDMI or DP.

Don’t know why…

Same issue here: 4k Dell on a CalDigit TS3 Plus. Worked flawlessly at 4k 60Hz over several OS releases and on different Intel MacBooks (Pro) and now with a 16" M3 Max and Sonoma i'm stuck at 30Hz ...

Setup has not change for at least 4 years. MBP -> Thunderbolt 3 -> CalDigit TS3+ -> DisplayPort 1.2 -> Dell

What's the point of a "Pro" Model with all the custom Apple Silicon at substantial expenses if one of the basic functions of Thunderbolt (daisy chaining with external displays) gets borked after working for years.

Apple, get this sorted!

I have just upgraded to Sonoma 14.2.1 and instantly have the same problem.

MacBook Pro (Intel Core i9).

I have two external monitors, both using HDMI-USBC connectors. All worked flawlessly before the upgrade, and now only the older monitor. My 32" Iiyama 4K is blank. This is my principal monitor for design work. I can;t function without it.

APPLE - Please sort this.

I had a problem with external drives, I did a clean installation of the Sonoma system and now the 2 Thunderbold ports have stopped working. The system test shows that everything is OK with the equipment. only when you roll back to the Monterey version does it work. The computer has a life of its own! It seems to me that Sonoma cuts off the power to the thunderbold ports.

Unbelievable such an issue that affects the extremely general use case of external display has not been addressed at all by Apply for almost half a year.

Pity for monitor vendors because 4K monitors now have zero value over FHD monitors.

I have a Mac Mini M2 Pro. I upgraded to Sonoma when 14.1 was available. I had one Viewsonic 4K monitor, and I was using the USB-C to USB-C cable. Around then end of November, I purchased another Viewsonic 4K monitor (not exactly the same model) with a USB hub. I added a 2nd USB-C to USB-C cable and both monitors were working great, even through a reboots or restarts. Then in Jan 2024 I noticed that on booting or a reboot, the new monitor would stay black. The status light would show a connection, display nothing, then the monitor went back into power save mode. I figured out that I could cycle power on the "off" monitor and then it displayed correctly. (like after every reboot, I would have to cycle power on the monitor to get it working) I disconnected all external devices including the older monitor, but the new monitor will not display on startup or reboot using USB-C now. I moved the new monitor to the Mac Mini HDMI output and now it works correctly again on reboots. Maybe something changed in Sonoma 14.2.1.

Same issue with 16 inch MacBook Pro 2021 M1Pro.

My external Redmi 27U sometimes just turned off for 5-10 seconds.

Previously its work fine, i tried different others same monitors in my office, different original Apple Type-c to Type-c cabbles, but it doesn't help :(

I found I could connect a DELL monitor, but when I changed (Unplugged and went to Viewsonic) that to my second monitor via a USB hub I could not connect. If I used a direct USBC to HDMI adaptor ( ( Vention 4k 60 Hz). it works.

I contacted OWC about this. I have their 4-port Thunderbolt 4, single USB 3.1 port hub. and my ViewSonic portable OLED doesn't work plugged into it using Ventura on Intel or M2MAX. They said this is a known Apple problem and they can't do anything about it.

And as for @Cougars_2010 - if I close my MBP, the directly-connected external screen image rotates 180 degrees so it is upside down.

Needless to say, I am not happy.

After updating to Sanoma 14.3, I still had darkness on my Dell, only after unplugging the USB C to display port cable many times I got an image. The image disappears as soon as I start moving the cable. This is crazy. Could it be that the Sonoma system was giving a weaker signal to the Displiy port? ???. I don't use any guides in the Ventura system, so it all worked fine for me.

Same issue. Upgraded to Sonoma and had a hard time getting two monitors to work. I had to go through my 5 docking stations (Yes, I have 5) from testing on Mac M1. Only 1 worked if I connect one monitor to DisplayPort, one to HDMI and set the DisplayLink software to enable experimental 3008 x 2560. If you don't enable the experimental option in DisplayLink it won't work. So try connecting one monitor to HDMI and one to DisplayPort. You may need to try a couple different docking stations which I know is crazy. All my docking stations worked on Ventura no problem and after the upgrade, major problems.

It looks like the display kernel was rewritten because when you boot, the external monitor does show the boot screen and what is happening at boot which is awesome. Ventura could not do this and I always had to open the laptop to login and let the DisplayLink drivers load.

I think this is heading in the right direction and they just need to work out the issues. A driver rewrite is always tough but it needed to be done to be able to see the boot information on the external monitor. I am sure they will fix it but it is frustrating for the time being.

It happened at the worst time for me too because my PC laptop crashed and I needed the Mac while my PC was being repaired (the Mac is my backup and travel machine) and I could not get the displays to work and I absolutely need two monitors as I program and do system admin work.

Don't go too crazy with trying to get your monitors working until they fix it.

[Edited by Moderator]

I have the same problem. I have two dell monitors and the mac m1 2020. I searched several topics and didn't find the solution.

My impression is that Apple doesn't care and doesn't give feedback, all the possible solutions I found here didn't work. I am using one monitor and the other is turned off (not in use).