Resolved Migration Assistant not using Thunderbolt between new M4 MBP and old Intel MBP

[mbsdf9345992]

I'm trying to use Migration Assistant to migrate from a 2016 Touch Bar MBP to my newly arrived 14" M4 MBP (base M4) via a direct USB-C/Thunderbolt connection. I spent an hour and a half on Apple chat support last night but we couldn't fix it. Both were/are plugged in to their chargers, and additionally connected via the Apple USB-C cable that came with my work MBP.

Today I completed basic setup then updated the new MBP from Sequoia 15.1 to 15.1.1 and started Migration Assistant again. The old MBP is running Monterey 12.7.6 which is latest supported MacOS on that model. Weirdly, this run of Migration Assistant started the transfer using "Ethernet" but after a while switched to "Peer to Peer". While debugging last night I tried looking at System Report on the old MBP while plugging the USB-C cable into all possible port combinations between the two machines. In a couple of them a "Mac" appeared in the USB section - not the Thunderbolt/USB4 section as expected - but it wasn't really repeatable.

Has anyone experienced or tried this? I'm worried my brand new machine has broken USB-C ports. I probably should have tried some external hard disks I have lying around before starting this Migration but I thought it'd actually finish in 1.5 or so hours so didn't bother!

Just to get going on the new one I'm migrating via Peer-to-peer now. Although it's making progress it's been saying 1 hour 20-something left for the past hour. Transfer speed is fluctuating between 40 and 55 MB/s. I expected to get at least 10x that via USB-C.

 

[PBG4 Dude]

Looking at Apple’s support pages they only seem to support migration assistant via WiFi? Couldn’t find any support documentation for using a wired interface.

 

[mbsdf9345992]

Migration Assistant helpfully informs me that if I plug in a Thunderbolt cable it might go faster. It's definitely supported. See this Apple thread and here on MacRumors.

BTW last "hour" of the transfer only took about 20 mins. Finally done and writing this on the new MBP.

 

[mbsdf9345992]

It also didn't work via Thunderbolt/USB-C between the new MBP and an M1 Mac Mini I happened to have sitting around.

 

[kitKAC]

Thunderbolt cables have a little lightning logo on the plug, ideally you should have been using one of those to connect your machines.

https://www.apple.com/uk/search/Thunderbolt+4+Pro+Cable?src=globalnav

 

[Bigwaff]

Both were/are plugged in to their chargers, and additionally connected via the Apple USB-C cable that came with my work MBP.

MBP don’t come with USB-C charging cables anymore. They ship with USB-C MagSafe charging cables. Unlikely your work sent you a TB cable just for charging.

 

[PotentPeas]

Indeed, despite the same physical plug, a Thunderbolt cable is not the same thing as a USB-C cable. You'll need to make sure that you're using an actual Thunderbolt cable for this to work. (Thunderbolt cables have an extra chip inside of the connector plug which facilitates the high-speed connection. USB-C cables are basically just wire with a plug on the end.)

 

[steve123]

As mentioned earlier the cable could be the source of your concern. One additional item to consider is that there are different types of USB-C cables. Namely, data cables and charging cables. Charging cables are only capable of transferring data at USB 2 supported bandwidths. Data cables can transfer data at USB 3.2 Gen 2 bandwidths (generally up to 10 Gbps). Generally you should confirm the cable type and bandwidth capabilities of your cables. Apple's USB-C charging cables are only capable of USB 2 supported bandwidths. Thunderbolt certified and USB4 cables are good up to 40 Gbps. But even with Thunderbolt and USB4 cables you need to be aware there are two types of these cables ... active (data chip and power chip built into cable) and passive (no data chip but has a power chip). To achieve 40 Gbps with a passive cable it must be no longer than 0.8m. Anything longer requires an active cable (cable with the data chip built in).

 

[Fishrrman]

I -always- recommend using an external backup for migration (usb or thunderbolt drive).

Things just go easier that way.
As the original post above illustrates.

 

[mbsdf9345992]

Yeah, it was the cable, thanks everyone. I kinda wondered about the lack of lighting bolt icon on the charging cable but the Apple Support guy seemed sure it'd work with the Apple cable.

This has been known since they first came out! E.g. this article here says:

Note in particular that the Apple-supplied power adapter charging cable, despite having USB-C ports on either end, is not actually a USB 3.0. USB 3.1 or Thunderbolt 3 cable.
It can't be used with another USB-C Mac to support Target Disk Mode or to transfer data via Migration Assistant. For that, you'll need a USB-C cable that supports USB 3 or USB 3.1 data.

I had a capable USB-C cable that came with my external display all along, but didn't think to try it! It also doesn't have the lighting bolt icon but when I tried Migration Assistant again just now it was zipping along ramping up to 90MB/s, having been "sampled" at 543 MB/s.