MacOS Big Sur, MacBook Pro 15 Late 2013, Thunderbolt Display

Hi,

I have exactly the same issue when my Macbook pro 13 retina late 2013 connected to my thunderbolt display.

I have opened a case with apple support. Been waiting on the phone for 2 hours to get senior support then I guess there is some automatic funtion on my iphone that disconnects the call after 2 hours. Will try to reach support again when they are less busy.

Last Saturday, I installed macOS 11.0.1 aka Big Sur a 2nd time using what I had learned from my initial experience. Thus, I plan to stick with it because I know that Apple will deliver an update to fix many of these issues. However, I do have a bootable USB drive with macOS Catalina as my backup plan in the event things get worse.

I can confirm the same Big Sur black login screen issue occurs on a MacBook Pro (Retina, 15-inch, Mid 2014) when the 27" Apple Thunderbolt display is connected at power on (my normal "home office" configuration).

When display cable is disconnected, the system boots normally to login screen.

If you try to connect the display cable prior to login, the login window will freeze and you need to reboot.

If you connect the display cable after login has completed, the external display is recognized and works normally.

I reverted my MBP back to Catalina via Time Machine and the same annoying display behavior now occurs under Catalina - it did not do that before. I suspect that some upgraded firmware is to blame.

No amount of PRAM or SMC resets seems to fix the issue.

More external display & device strangeness this morning during (cold) boot up - I had powered down my MBP last night.

FYI - I have a LaCie 2 Big Dock external RAID array connected via Thunderbolt 2/3 adapter & short cable to the back of my 27" Apple Thunderbolt display. It has been connected this way with no issues through all my previous Big Sur upgrade, Catalina restoration, SMC/PRAM reset and "display cable unplugging prior to boot" adventures. The external RAID array holds several storage/archive volumes, SuperDuper backups and my Time Machine backup.

With display cable disconnected, MBP boots up and I login and wait for the usual startup programs to complete. Upon plugging in the display cable I expected the external display to light up and the external disk volumes to be mounted - which is how it worked for the last few days. However, now the system freezes and then crashes during external disk mounting. ***?

I disconnected the external disk array from the external display, disconnect the display from MBP and booted up again. I get the external monitor to function after reconnecting the display cable, but now the system freezes & crashes when I connect the external RAID array to the external display. Double ***??

Do I now have a bad external disk volume that can't be mounted? I boot up the MBP with no external devices connected. I found a longer Thunderbolt 2 cable and connect the external RAID array directly to the MBP to check the disks. All the external disks mount and are OK.

I disconnect all external devices from the MBP and performed SMC and PRAM resets.

I returned my external devices to their usual configuration (external array daisy chained off the external display), and boot up with the display cable disconnected. Upon plugging in the display cable the external display lights up, then the system freezes and crashes during external disk mounting. More ***?

So I tried it a different way - reboot again with no external devices connected. Connected up the external RAID array directly to the MBP and all disks are mounted. Connected up the external display and it comes to life. Things are working again. System has not crashed (yet!) - I am using it to write this post.

Is this the new normal now? Figure out which combination external devices to connect & when after boot up?

This whole Big Sur upgrade experience has been fracking frustrating!

I have the same issue with the same configuration (minus Bootcamp):

Upon startup:

• When my Apple 27" Thunderbolt Display is connected:
  • My MacBook immediately has the blank, blackish, backlit screen.
  • The Thunderbolt Display is completely black (not backlit).
  • I hear the Startup chime twice with a brief pause in between.
• When my Apple 27" Thunderbolt Display is not connected:
  • Startup is successful.
  • I can connect the Thunderbolt Display after Startup and both screens work as they should.

My configuration:

• MacBook Pro 15 (late 2013)
  • Processor: 2.6 GHz Quad-Core Intel Core i7
  • Monitor: 16 GB 1600 MHz DDR3
  • Graphics: NVIDIA GeForce GT 750M 2 GB
• Apple Thunderbolt Display 27"
• WD My Passport for Mac 2TB

I disconnected external devices and re-installed Big Sur. It made no difference.

-Phil

-Phil

Hi, here are the written steps of downgrading from macOS Big Sur to Catalina:

https://www.globalnerdy.com/2020/11/18/how-to-downgrade-to-macos-catalina-after-upgrading-to-big-sur

If you have any questions before you start, please do post here. Next, if all goes well, you shouldn't loose any of your user related data because Apple has created a container that separates your internal HD (i.e. a container) into 2 volumes called MacIntosh HD (i.e. OS components) and MacIntosh HD - Data (i.e. all the user data). However, you may have to install and/or configure any applications. Finally, you should have backed-up everything that you care about before you begin this process even if it is just copying stuff to an external HD. Good luck and all the best.

--

Think different and code well,

-Conrad

I have the same issue on Big Sur with a 2016 MacBook Pro and 27" Thunderbolt screen. Can get the screen running but if Mac goes to sleep then I have to re-boot. Plus when thunderbolt camera, usb port's or speakers work. Its an awful thing to have a perfectly good piece of kit being made redundant by a company that is supposed to support recycling!

[Edited by Moderator]

OUM2303279 wrote:

I'm sorry, I can't get past the annoyance of having my previously very functional Macbook and its many associated peripherals for both business and music rendered unusable by an 'upgrade' that has no way for me to safely back out.

If you had made a Time Machine Backup or a clone before the upgrade

(which you should be doing anyway for a business computer) you can

simply restore to the previous version. So there is a way to "safely back out".

And if you were not doing that, then it was an accident wait to happen, OS

upgrade or not.

The firmware for the thunderbolt screen has also been changed on Catalina when you upgrade to BIg Sur. So even if you do go back you get the same issues with that problem. This is why the fix has to be for both Big Sur and Catalina OS.

I can confirm that the firmware fix is in the latest Catalina update too - I can now boot up my Mid-2014 MPB with my 27" Apple Thunderbolt display and other Thunderbolt & USB accessories connected. However, you will need to disconnect all those devices (for the last time) prior to installing the Catalina update - otherwise you will get the black screen again on the install reboot. Once the update installation finishes (about 25 minutes) everything works as expected again - no SMC or PRAM resets were required.

I also upgraded to Big Sur when it was released, and reverted back to Catalina via Time Machine. I will likely stick with Catalina until my backup utility (SuperDuper!) is released for Big Sur.

Strangely, in the reboot immediately after installing "the fix", my Apple Thunderbolt display audio & video were also not working - no "Display Sound" output, and System Preferences > Sound and FaceTime would hang. A second reboot seems to fix this - camera & sound now work for me. No PRAM or SMC reset required.

Hi,

I have completely similar problem in my MacBook Pro (Mid 2014). I can not use Thunderbolt Display with windows after updating Mac OS to Big Sur.

I had started a separate thread on this same issue. So it is being widely reported.

Apple finally acknowledged this problem.

https://support.apple.com/en-us/HT211242

Much of this we already tried. Anyone get further with Apple Support?