Migration Assistant: Thunderbolt to USB-C slow?

This seems to be the issue we are dealing with:

Target disk mode very slow in one direction

The issue surfaced with Boot ROM Version MBP112.0138.B18 that was introduced with Sierra. Machines can update to that version without Sierra.

I think you should read it again. It clearly states that. Also I am pretty sure that cable transfer speeds should be “a bit” faster than wifi transfer speeds:

Or connect them using target disk mode and the appropriate cable or adapter. Then start up your old computer in target disk mode.

You can move data between two MacBook or MacBook Pro computers equipped with USB-C using a USB-C to USB-C cable.

How is your imagination working out?

Select the categories of content you want to transfer. Click Continue. Then click Agree on the next two Terms and Conditions screens to start the transfer. Depending on how much content you have, the process might take several hours.

Your best bet and the fastest would be by

Over Ethernet with an adapter

All I can tell you is there are basically 3 supported methods you can use…

1. Over WiFi.

2. From a Time Machine backup

3. Over Ethernet.

If you want to jerry rig a different method, whatever the outcome is what it is.

I don't know what the problem is, but I have to say your method is a perfectly valid one. Your older mac supports target disk mode over thunderbolt. As soon as it starts in that mode it becomes a thunderbolt drive for all intents and purposes. And this is the fastest connection available for it. Either there is a problem with the adapter or the setup or something else. Don't accept the idea that you were somehow doing it wrong.

FWIW I have done a similar thing very successfully - the only difference is mine was from a thunderbolt 2 mac to another.

A clarification is in order!

dialabrain wrote:

If Luis says he has connected a 2016 MacBook or MacBook Pro with USB-C ports via TDM and a Thunderbolt cable utilizing Setup Assistant to an older MacBook I have no reason to doubt him.

1) A MacBook has USB-C ports that are NOT Thunderbolt 3. Using Migration Assistant in the way described would not work on a 12" MacBook

2) A 2016 MacBook Pro has four (or two for the non-touchbar model) Thunderbolt 3 ports. These use the same USB-C type plug and can be used as regular USB-C. The converse is NOT true (the 12" MacBook CANNOT use Thunderbolt at all - here's hoping a new 2017 model rectifies this).

3) With an Apple TB3->TB2 adapter, one can connect TB2 peripherals to a 2016 rMBP; they will be limited to TB2 speeds (which is not a big limitation; odds are the peripherals cannot saturate the TB2 bus). A TB2 equipped Mac in target mode is one relevant example of one such peripheral. Even its fast pci-e SSD would not saturate the TB2 channel - meaning the transfer should as fast, but not faster, than when connecting two TB2 macs.

What I said is this:

a) in situation 3, there is no reason to suspect Migration Assistant would not work reliably to bring stuff from a TB2 equipped Mac to a 2016 rMBP.

b) I do not have a 2016 rMBP (though I accept offers :-)), but I did this migration to transfer info from a TB2 mac to another. There was obviously no adapter involved, just a direct Thunderbolt cable between the two Macs.

I submit that unless the adapter is somehow faulty, it should not impede a fast migration.

The method the original poster tried is the one I would/will try today (should someone graciously offer me a new mac - come to think of it, it's my birthday :-))

I am having the exact same problem, on the same machines. I am using a TB3 to TB2 adapter and a TB2 cable (all from Apple). It starts at near 100 Mbps then steadily drops to about 10 Mbp. Tried 2 different cables and adapters. Tried TDM and straight migration assistant. Once migration was complete (10-12 hours), the user account was unusable. Constant beach balls, won't authenticate to web services like iCloud. Spent days on it and hours online with Apple support. Still no solution. Did Apple just become Microsoft? So far I hate the late 2016, I hate USB-C and I am contemplating next moves. This is my second $4500 late 2016, my first one failed the power test at the Genius Bar and was sent back. After another 6 week wait, I am now once again in migration ****.

I am having the same issue using TDM on a Late 2013, Retina, 15" MacBook Pro copying data to a new USB-C MBP. BoukeH, as Luis said, your setup is perfectly valid and anyone you suggests otherwise is wrong. I'm starting to think the issue is with the source machine's TDM as my speeds when putting the new machine in TDM and transferring from the old machine (MBP late 2013) are extremely fast. I'm going to find another late 2013 MBP and test this theory.

I'll let you know what I find.

Probably you are not using the right cable. It is an unfortunate thing that not all USB-C cables are the same.

The USB-C charge cable that comes with your mac does not support the full data transfer speed, it only supports data transfer at up to USB2 ⚠ speeds.

Different boat, same issue. Bought all TB-1 accessories for my 2012 MBP years back. Bought 2017 MBP with USB-C and had to get adapters (grrrrr). Migrating took many hours. Now I'm migrated but even backups are ridiculously slow. Not the preparation, its the file backup. 2 hours for 30G...

Feels like 5 years forward, but 2 steps backwards.

Kanefire wrote:

Different boat, same issue. Bought all TB-1 accessories for my 2012 MBP years back. Bought 2017 MBP with USB-C and had to get adapters (grrrrr). Migrating took many hours. Now I'm migrated but even backups are ridiculously slow. Not the preparation, its the file backup. 2 hours for 30G...

Feels like 5 years forward, but 2 steps backwards.

Two hours for 30GB is slow! Is that using Time Machine?

What drive are you backing up to?

Is copying a few large files also that slow?

Seagate Goflex Pro with thunderbolt... was quick for my 2012. Also got the apple USB-C to TB 1 adapter. Guessing this is where the bottleneck is. It's pretty frustrating that they come out with proprietary ports and discontinue them after a single generation. Could have added at least once TB port...