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

Same issue here on MacBook Pro M2 with an external 4k LG monitor. It was working fine in Ventura. It is not recognized in Sonoma via USb-C. It works via HDMI. However I have two external monitors and need to use USBC for one. apple please fix this ASAP!

months and months later… post after post like this and Apple just acting like it doesn’t exist 🤦🏻‍♂️

literally every OS prior worked. Why is this so hard for them to fix in Sonoma??

UPDATE. I backed up my MB Pro with Time Machine, created a bootable disc with Ventura on it, erased my internal MB hard drive, reinstalled Ventura with the bootable disc and now my Thunderbolt monitors work flawlessly again. Sonoma is definitely the culprit. Get yo stuff together Apple. Sheesh. Pry this Ventura from my cold dead hands until they acknowledge they've fixed monitor support issues...

What I found was that resolution is not coming up properly. For my hp27xq which supports 2560 X 1440 resolution is only able to give 1920 X 1080 resolution. SS attached.

also this was working fine before upgrading to Mac OS Sonoma.

If anyone can help with this, it would be much appreciated.

Thanks

Right I don’t get it. It’s clearly not a cable issue…. especially for me when my “APPLE THUNDERBOLT display” Thunderbolt cable literally cannot be removed from the display or replaced - it’s attached to the inside of the display by Apple. 😂

it’s just unbelievable it’s been this long and still no fix. This is a major issue and causing lots of issues for many home offices like mine.

27” iMac (2020)

27” Apple Thunderbolt Display

wish it would “just work” like it did for the past 4 years 🤷🏻‍♂️

It’s 100% Sonoma. Nothing is wrong with my machines. Worked flawlessly for 3.5 years as a pair. Through every update and upgrade of macOS. The very same day I upgraded to Sonoma it’s been consistent issues. I thought about downgrading from Sonoma as I use this setup for work…

Also, the nearest Apple Store is about 2 hours away from my house so that’s not an option.

I have just 'downgraded' my OS back to Ventura and everything works normally now. Ngl, I think I spent too much time troubleshooting this issue and even Apple Store Techs are not aware of it. I will soon contact the online support and get a Tier 2 Data Capture and see what actually happened.

To get OS Ventura back, you have to back up everything using Time Machine.

Erase your mac.

Restore your mac to its original OS (Say mine is Macbook 2019, so it will get back to Catalina)

Download Ventura on App Store.

Install it Ventura, restore all your files.

Violà :)

Had the same issue with my LG monitor.

Unplugging my monitor for 10+ seconds from the wall socket did the trick.

@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.

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"...

In my case, it was the monitor. I had to go into the menu and change the color profile to something else and it cleared right up! Just putting this in case it helps anyone down the road. M1 Sonoma, 1080P Asus monitor on HDMI.

M1 macbook air no longer detect external display after Sanoma OS update

same issue with Samsung 34 inch curved monitor. monitor is recognized for a second or two before disconnecting and this repeats. unfortunately monitor has only 50/60Hz options and monitor doesnt work in either settings.

Same here.

My MacBook Pro with

Processor: 2,6 GHz 6-Core Intel Core i7

Graphics: Intel UHD Graphics 630 1536 MB

is unable to connect to the thunderbolt Display after the upgrade to Sonoma (14.0).

I can connect, but after a few seconds the display goes black. I tried restart with Option+Command+P+R key until 2 times restart sound (resetting NVRAM/PRAM), unplugging the power from the display and waiting 10 seconds. Nothing works.

Same - Sonoma has changed the way Thunderbolt is put to sleep and is causing issues! This is a Sonoma problem, not the display or the cable!

2023, 14" M2 Pro running Sonoma 14.1 (and hoping the update of the week may fix something!)

Display is a LG 34WK95U 34" UltraWide 5K

For years the external monitor has worked flawlessly with both an Intel i7 16" and this M2 Pro 14".

After upgrading to Sonoma, every time my mac goes to sleep, the Thunderbolt Display is not recognized. I restart and everything works as expected, but all of my desktops have been rearranged and windows moved - which is my biggest problem!

Unplugging & restarting the monitor does nothing. Using a different 40gbps thunderbolt cable does nothing. I also have a Thunderbolt 2 Dock connected to HDMI & VGA cables that has continued to work fine, but the 5k Thunderbolt 3 monitor is lost after the screens go to sleep. Only restarting the mac finds it again.