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

ALL SORTED...

I spent hours on the phone with Apple Ireland about this issue last week and they remotely took over my Macbook Pro and did loads of unfathomable tech stuff as I watched, including taking time-stamps of actions they did, as they occurred in real time.

They rang me to let me know that they were about to release macOS Big Sur 11.1 and that the engineers had inserted some coding to hopefully sort my/your issue.

They rang again tonight and asked me to download, install and restart to test it, and they waited while the install occurred etc.

And it works.... Macbook now happily reboots with Thunderbolt monitor attached, etc

Feel free to send me £10 notes in brown envelopes to show your eternal gratitude ;O)

Happy Christmas one and all.

Giles

For those still interested. I got my setup working as normal. I unplugged the power for my Thunderbolt screen from the shielded adapter and plugged it straight into a wall socket. Booted up MacBook and plugged screen in - and camera , usb sockets and speakers working as they should (all dead before on 11.1 latest upgrade) - so far. Cannot believe it was just that power setup? Go figure - but there you go.

👍🏼Big Sur 11.1 fixed my issue, too. I am able to both Restart and Shutdown/Start with my Apple 27" Thunderbolt display connected.

My original issue: I could not start my MBP with the Apple 27" Thunderbolt display connected. I had to disconnect it, start, then reconnect it. I did not have any other issues.

Model: MacBook Pro (Retina, 15-inch, Late 2013)

Processor: 2.6 GHz Quad-Core Intel Core i7

Memory: 16 GB 1600 MHz DDR3

Graphics: NVIDIA GeForce GT 750M 2 GB

-Phil

Found a solution, albeit a silly one at that. I had my setup plugged entirely into a surge protector, as one does when working with expensive equipment. This was causing the problem, at least for this issue.

> Shut down external displays

> Shut down main iMac

> Unplug Thunderbolt cables from external displays

> Unplug main iMac from surge protector

> Plug main iMac into a wall socket, leaving the external displays plugged into surge protector

> Boot main iMac

> Boot external displays

> Plug external displays back into Thunderbolt ports

Hoping Apple figures out a permanent solution, considering I now have to reposition half of my office to accommodate for the short power cables that iMacs come equipped with.

The problem cleared after upgrade to macOS 11.1

MacBook Pro 15" Late 2013.

Thanks for all of you guys that push Apple fix it.

When I last spoke with my Applecare Senior Advisor last week, I was told that this is a known issue by the engineering team and a patch will be coming in a forthcoming release of macOS (i.e. Catalina & Big Sur). Why Catalina? If you upgrade to Big Sur, it will update to the newest boot ROM version. Now, if you downgrade to Catalina, it will not downgrade the boot ROM version back to the previous version. Thus, the issue that one experience in Big Sur will persist after downgrading to Catalina. In short, a patch will be created to resolve this issue at some point. Furthermore, I'm not planning to upgrade from Catalina to Big Sur again until mid February 2021 because this will give me some time to research application and hardware compatibility.

Did you try reset P-ram after revert back to Catalina?

advise by Taylor above the thread:

During my first try of installing macOS Big Sur, I reinstalled Catalina and noticed a similar black screen issue. However, I was able to correct it by doing a Restart + PRAM reset (i.e. Command + Option + P + R). Then I double checked with my Apple Thunderbolt Display connected by doing another Restart and I was able to successfully boot into macOS 10.15.7 (Catalina) without a black or blackish screen.

Sleep/PowerNap functionality also is affected after reverting back to Catalina. I went to lunch and came back to a black screen again. Needed to unplug the Thunderbolt display after powering down & booting up.

Tried PRAM and SMC resets - no luck at all. I continue to suspect that bad firmware was loaded during the Big Sur upgrade.

Jake, have you installed the very recently released Big Sur 11.1, as that should sort you.

Issues resolved. I physically disconnect Thunderbolt and power, rebooted, and wa-la. Thanks all.

Thank you. I'm glad I'm not alone or imagining things. I only wish I'd seen your post earlier!

I've had a very frustrating 24hrs trying to get Big Sur to work properly with my setup of MacBook Pro (Retina, 15-inch, Mid 2014) and 27" Thunderbolt display. The upgrade appeared to fail and booted to a black screen.

• I reinstalled BS through (Command-R) and that didn't work.
• I reset the NVRAM - no change.
• Many restarts later, I discovered that it worked in stand alone mode when there were no external devices.
• There were no issues with returning from sleep mode.
• The Thunderbolt monitor works as normal but only if connected after MacBook has booted normally. On restart, boot will fail if still connected.

Many resets/restarts, shutdowns later, I have concluded that the issue is starting with the Thunderbolt display connected (and with it my ethernet connection and thunderbolt 2 connected Time Machine drive).

Since the Thunderbolt display is obsolete, I can't see Apple doing anything about its firmware. I hope they can find a work around as it's a pain having to reconnect every time.

I will report this to Apple as well.

During my first try of installing macOS Big Sur, I reinstalled Catalina and noticed a similar black screen issue. However, I was able to correct it by doing a Restart + PRAM reset (i.e. Command + Option + P + R). Then I double checked with my Apple Thunderbolt Display connected by doing another Restart and I was able to successfully boot into macOS 10.15.7 (Catalina) without a black or blackish screen.