Mac to Mac with Thunderbolt

Question

Mac to Mac with Thunderbolt

I have a 2021 14 inch M1 Pro running Ventura 13.5 and a late 2015 27 inch Retina iMac with Monterey 12.7 . I am trying to use the Thunderbolt bridge using an Apple Thunderbolt 3 to 2 adapter and an Apple Thunderbolt 2 cable. The bridge does not initially connect. When I reboot both machines the connection is made and everything works perfectly and they will remain connected for long periods of time. When I unplug the cable (on either side) and plug it back in the connection is never made. So to clarify I must reboot both machines every time I connect them together. What can I do to fix this?

MacBook Pro 14″, macOS 13.5

Posted on Oct 22, 2023 6:15 AM

Reply

Answer 1

Top-ranking reply

Servant of Cats

Level 6

17,044 points

Oct 22, 2023 6:48 AM in response to samfromrhinebeck

I assume that you're not trying to use Thunderbolt Target Display Mode … neither of your Macs support it.

Use IP over Thunderbolt to connect Mac computers - Apple Support

How are your network parameters configured for the Thunderbolt interfaces. Apple says "If needed, you can enter an IPv4 address manually" (without going into the cases where manual configuration might be needed). Could the issue be that there is some hiccup with automatic (BootP) configuration?

Reply

Answer 2

Oct 23, 2023 5:08 AM in response to Servant of Cats

No target display mode never made it to the age of Retina on iMacs. I am actually using Luna Astropad which works brilliantly over Thunderbolt. It really is like having the Imac as a second monitor with smooth scrolling and has keyboard mouse remoting as well. For diagnostic purposes, however, I am just observing the connection status under networking with objective of being able to disconnect the cable and reconnect it and have the status show it is connecting.

Initially I was just allowing self assigned ip addresses. In that case after rebooting both machines both sides were active and the yellow indicator was showing. Of course on disconnect / reconnect it would never reconnect. As per suggestion above I tried manually assigning a pair of IPv4 addresses on an unused sub-net. Then after reboots one-side says it is connected and it displayed green and the other says "unknown state" and displayed yellow. Of course once you unplug it and plug it in again it says "disconnected" on both sides and never will reconnect without a reboot. Very frustrating.

Reply

Mac to Mac with Thunderbolt

Similar questions