Error "This Mac was unable to start a high performance connection ..."

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Level 1

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Error "This Mac was unable to start a high performance connection ..."

I am trying to connect my Mac Pro M2 Ultra to MBP 16 M2 Max. Weirdly, I can easily start the connection in High-Performance mode, and it works for a few seconds, and after that just goes to message "This Mac was unable to start a high performance connection...".

Everything works as expected when I use Normal mode.

And just to clarify, I am connected with the Thunderbolt 4 cable between Mac Pro and MBP. Also, Mac Pro is on 10Gbps network, MBP on 2.5Gbps, and they are both connected to 6E WiFi. I don't see how much faster I can make this connection.

[Edited by Moderator]

Mac Pro (2023)

Posted on Mar 9, 2024 5:19 PM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

139,553 points

Jun 13, 2024 9:32 AM in response to outcoldman

The highest-performance ThunderBolt connections, such as those for high resolution displays, require an Apple-brand ThunderBolt cable of length 0.8 meters of shorter, or a brand-X Thunderbolt cable of length 0.5 meters or shorter.

In every case, the cable should carry the Thunderbolt trademark indicating it is a certified Thunderbolt cable.

When "perfectly good" longer cables are used, Transmission errors may start to occur, and this could force the connection to drop out of fastest speed to a slower speed.

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Answer 2

Mar 19, 2024 5:51 AM in response to outcoldman

Same here. Just spend an hour testing with Apple Care.

It appears I do not get the error if the connection is to a new admin account on the target ("server") Mac.

I tried disabling all software that opens at login on the target Mac without success.

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Answer 3

Jun 13, 2024 10:36 AM in response to gk76

see if this reference article has anything that helps:

Use High Performance screen sharing - Apple Support

.

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Answer 4

gk76

Level 1

0 points

Jun 13, 2024 10:20 AM in response to Grant Bennet-Alder

Sure, I have bought an apple brand 0.8m just before installing Sonoma 14.5.

Before that the high performance connection was stable also on the local WiFi connection.

Using the thunderbolt connection, after setting the thunderbolt bridge IP ( no dhcp) it worked for a couple of weeks most of the time.

After a while, the problem comes back!

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Answer 5

May 1, 2024 2:03 PM in response to outcoldman

Hi, I've the same problem, with error "This Mac was unable to start a High Performance connection to...", I'm trying to connect from a Macbook Air M2 to a Mac Mini M2 Pro. The problem is still present and started 1 week ago. Both macs are on Sonoma 14.4.1, but I can't relate the broken screen sharing with the update. I havn't find anything useful on logs or online

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Answer 6

Mar 25, 2024 11:58 AM in response to outcoldman

No improvement with macOS Sonoma 14.4.1 :-(

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Answer 7

May 1, 2024 9:17 AM in response to outcoldman

+1 on this. spend an hour with support but that wasn't any helpful. 2 MacBooks M1 2020, same 14.4.1, same network, firewall disabled. anyone had any progress in troubleshooting this?

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Answer 8

May 1, 2024 9:22 AM in response to outcoldman

Mine now works again, although I am still on macOS 14.4.1 on both machines and haven't changed anything in my network.

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Answer 9

gk76

Level 1

0 points

Jun 13, 2024 4:04 AM in response to jeromec71

Same here on 14.5 with Apple thunderbolt cable, same network :((

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Error "This Mac was unable to start a high performance connection ..."

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