Thunderbolt 3 to Thunderbolt 2 adapter Not working

Question

Thunderbolt 3 to Thunderbolt 2 adapter Not working

I got a brand new Apple Thunderbolt 3 to Thunderbolt 2 adapter. It does not show up as connected to Thunderbolt in System information. And when I connect a USB-C keyboard nothing happens. Connecting the keyboard with a USB-A -> USB-C cable works.

I have mid 2014 MacBook Pro with two Thunderbolt 2 ports and want to connect some USB-C peripherals, not the keyboard but that was a good test.

With a regular cable the keyboard works. With Thunderbolt cable + adapter it does not.

Is the brand new adapter faulty?

Posted on Mar 18, 2021 3:58 AM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

141,823 points

Mar 18, 2021 7:20 PM in response to Ingmar Hemsen

The ThunderBolt-3 <-> ThunderBolt-2 adapter supports ThunderBolt devices ONLY, it does not support USB-C devices, does not support any other types of displays and does not support adding any adapters to the outboard end.

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Answer 2

Mar 19, 2021 9:19 AM in response to Ingmar Hemsen

ThunderBolt-3 is an uncommitted computer port that can do almost anything, with the right cables/adapters. The first cable/adapter you attach customizes the port to one particular purpose, usually a more narrow subset of all it could potentially do.

If you plug a ThunderBolt cable into a ThunderBolt port on a computer, that will support Thunderbolt devices. And at that point, it will not support any other types of devices. The computer port is the magical one that can be customized -- all other are already committed to another purpose, and you generally cannot "stack" adapters to customize them further.

About the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple Support

.

Unless you have a ThunderBolt keyboard, that ThunderBolt-3 <-> ThunderBolt-2 adapter is not the right tool for the job.

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Answer 3

Mar 22, 2021 8:32 AM in response to Ingmar Hemsen

That device supports ThunderBolt devices, ONLY. Your keyboard is NOT a ThunderBolt device.

Nowhere does it state that the outboard end of the cable can be further customized by applying additional adapters. I told you above that the outboard end of the cable Does NOT accept any further adapters.

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Answer 4

Mar 22, 2021 3:20 AM in response to HWTech

Hi HWTech,

the idea was to be able to use the new Thunderbolt 3 docking stations at work. I posted a question here a while ago which was not answered (https://discussions.apple.com/thread/252552086). I also found this post which says that you can connect the way I did: https://discussions.apple.com/thread/8234948

So I decided to test it and got the Thunderbolt 3->2 adapter, a Thunderbolt 2 cable and a female to female USB-C.

Well. It doesn't work. QED.

The "bidirectional" Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter only connects Thunderbolt 3 computers to old Thunderbolt 2 devices. https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter

Citation:

Product information [...] "As a bidirectional adapter, it can also connect new Thunderbolt 3 devices to a Mac with a Thunderbolt or Thunderbolt 2 port and macOS Sierra or later."

I think that sentence is misleading if not altogether wrong.

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Answer 5

Mar 22, 2021 9:34 AM in response to Ingmar Hemsen

A USB-C cable is NOT a ThunderBolt cable. It has far fewer conductors.

USB-C is the name of the Connector, ONLY. The type of cable SHOULD be more fully explained on the box. USB-C cables are NOT NECESSARILY ThunderBolt cables. You need to look for the ThunderBolt symbol on each and every item you plug in if you expect ThunderBolt support.

Adapters for the Thunderbolt 3 or USB-C port on your Mac or iPad Pro - Apple Support

Look carefully at the pictured connectors in the article above.

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Answer 6

Mar 19, 2021 7:12 PM in response to Ingmar Hemsen

Universal connectors like the USB-C connectors are very confusing even to techs sometimes. The main thing you need to do first is understand what protocol your peripheral uses to communicate with the computer. A keyboard doesn't need to use a fast protocol so a Keyboard will usually just support the USB protocol. Once you know that the peripheral uses the USB protocol, then you can look for cables & adapters to work with it.

If you want to use that USB-C keyboard with the 2014 laptop, then you need to use a USB-C Female to USB-A Male Adapter like this one:

https://www.tripplite.com/usb-c-female-to-usb-a-male-adapter~U329000

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Answer 7

Mar 18, 2021 7:16 PM in response to Ingmar Hemsen

If your USB-C keyboard doesn't work as well, then it implies your laptop has a hardware issue with the USB-C ports. Make sure all other external devices are disconnected just in case one of them is actually causing the problem. Have Apple or an Apple Authorized Service Provider examine the laptop to provide you with a repair estimate.

Try using another USB-C port especially on the other side of the laptop if you have four USB-C ports. Also try rotating the USB-C connector 180 degrees upside down (sometimes this will work when the I/O Port or Logic Board has problems). This may allow you to limp along until the laptop can be repaired.

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Answer 8

Mar 19, 2021 6:35 AM in response to Grant Bennet-Alder

Hi Grant,

My MacBook Pro does not have any USB-C ports. Just two Thunderbolt 2 ports.

If the adapter lacks support of USB-C, it will of course explain why things don't work. But the adapter is called "Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter" so it is fair to assume at least some support for USB-C. On the back of the package it is clear that it does not support DisplayPort or Mini DisplayPort which has the same plug as Thunderbolt 2.

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Answer 9

Mar 22, 2021 9:11 AM in response to Grant Bennet-Alder

Grant,

the keyboard was just a test especially since the adapter does NOT show up as connected to the Thunderbolt 2 port when connected with a Thunderbolt 2 cable. Other Thunderbolt 2 adapters I plug into my Mac show up as connected when looking at the System Information app.

And the adapter does apparently NOT support all Thunderbolt devices, like this Thunderbolt docking station: https://store.hp.com/us/en/pdp/hp-thunderbolt-dock-120w-g2

I appreciate that you told me that the adapter does not accept any further adapters which apparently also include any cables? A female to female USB-C is more or less equivalent to a very short cable with two female ends.

To all readers:

I have now tested this. It does not work. Mark the thread helpful if you are helped.

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Thunderbolt 3 to Thunderbolt 2 adapter Not working

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