Thunderbolt Display not working with M1 Mac Book Air Running Sonoma 14.5

Question

Level 1

4 points

Thunderbolt Display not working with M1 Mac Book Air Running Sonoma 14.5

When I plug in my Thunderbolt display (which works seamlessly with my older Macbook Pro Mid 2012 running 10.15.7) into my new M1 Mac Book Air running Sonoma 14.5 I get a blink of "allow accessory to connect? Do you want to connect Thunderbolt Display to this Mac?" but then it automatically closes. It appears that the software is immediately killing the attempt to connect the display. I literally had to screen record and slow down frame by frame to see the notification. As an FYI, I am connecting via both the "octopus cable" with a TB to USB-C connection and also a direct TB to USB-C connector (all apple branded connectors).

So, the question is, is there a way to connect my new machine to the Thunderbolt Display? Why is the software automatically killing the attempt to connect?

This appears to be either a bug in the software or an intentional blockage written to disallow using older displays.

Anyone have any thoughts?

[Edited by Moderator]

MacBook Air, macOS 14.5

Posted on Jul 1, 2025 11:29 AM

Reply

Answer 1

Jul 1, 2025 04:03 PM in response to bjhawkins59

bjhawkins59 wrote:

When I plug in my Thunderbolt display (which works seamlessly with my older Macbook Pro Mid 2012 running 10.15.7) into my new M1 Mac Book Air running Sonoma 14.5 I get a blink of "allow accessory to connect? Do you want to connect Thunderbolt Display to this Mac?" but then it automatically closes. It appears that the software is immediately killing the attempt to connect the display. I literally had to screen record and slow down frame by frame to see the notification. As an FYI, I am connecting via both the "octopus cable" with a TB to USB-C connection and also a direct TB to USB-C connector (all apple branded connectors).

Is this a Thunderbolt Display whose cable has TWO heads? Or a LED Cinema Display whose cable has THREE?

The Thunderbolt 1 ports on mid-2012 MacBook Pros could double as Mini DisplayPorts. Thus they would have worked with either type of display. Adapters only produce one type of signal. So

For a Thunderbolt Display, you would use an Apple Thunderbolt 3-to-2 adapter.
For a LED Cinema Display, you would use a third-party USB-C to Mini DisplayPort (female) adapter.

If you are using the right adapter, the cable may be flaky. Recent versions of macOS are reportedly intolerant of transmission errors – as in, they may cut signal if they see any. With a Thunderbolt Display, it may be possible to bypass a bad cable by running a TB 1/2 cable into the monitor's TB daisy-chaining port.

Reply