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

@iturn2...now that's messed up since both are Apple products. I know its a pain...but have you tried the Apple store? like bringing uour iMac & display for them to figure it out?

Yea..I tried the cable recommendation and that didn't work for me.

I upgraded to sonoma and the external monitor won't work. I've restarted multiple times, unplugged, power cycled the monitor, the docking station. Not sure what else I can try. Checked settings on the Dell monitor. Please fix!

I was good after 14.1.1 on an m1 Air with an LG 24” 4k Ultrafine.

I saw a local listing for the current 5k apple monitor and the person was selling bc they had problems with their m2 Mac Studio on 14.1.2

Time for people to start explicitly listing their configs so the tail chasing or uninformed speculation tamps down.

I'm not a techie so may be missing something.

I've been running a 2020 MacBook Air with a 4K BENQ monitor and it's worked just fine.

I've just bought a 2023 MacBook Pro 14" m3

On first boot I got an instruction to update the OS - not realising it was going to load Sonoma.

I'm therefore unsure if it's Sonoma creating my issues or the MacBook Pro.

On connecting the new MacBook Pro to the BENQ I get some weird results.

The background wallpaper is the only thing displayed on the BENQ - not the contents/folders etc showing on the laptop screen?

Having the same issues with my two Thunderbolt displays with MBP 13-inch, 2020, Four Thunderbolt 3 ports. Use Apple adapters for the displays and had no issues until upgrading to Sonoma. It's even worst with 14.2 . Complete s@#t show.

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

Over 3 months since Sonoma release, its mind boggling to me that every day I sit down at my office and move my mouse, I sit and wait to see if BOTH monitors turn on, or if I have to reboot my iMac again to get my Thunderbolt Display to be recognized... Apple to Apple product - first time since probably 2008 I can remember it doesn't "just work"...

@opers13 works most days…. It’s just really frustrating randomly, weekly I go to my office and my drives are disconnected and not recognized and my Thunderbolt Display is unrecognized until I do a full restart. Makes no sense. It’s not even consistent, outside of it just started since Sonoma release.

Does not work over HDMI ... same issue, 60Hz was working just fine on my Samsung 43" QLED HDTV before upgrading to Sonoma. Now I can only get up to 30Hz -very frustrating.

Unplugging, rebooting, NVRAM resets -nothing will restore my 60Hz setting. May go back to prior OS.

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.

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 :(