Questions & Answers for Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter

Just tried to connect a 2015 5K iMac with TB2 to a Lacie USB-c/TB3 hard drive using this adapter and it did not work. The drive works with a USB-c to USB3 cable so it seems that not all peripherals will work with this adapter on older iMacs.

• Answered by Michael P from Beacon Hill
• 24/11/2018
• Flag as inappropriate Answer (TB3 peripheral (AKiTiO Thunder3 Quad Mini) with 2013 iMac 27 TB1?)

No. See the Apple support document HT207266 "Connect devices and displays with the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter".

Use a USB-C to Mini DisplayPort cable instead.

• Answered by Joseph V from Fort Langley
• 20/12/2016
• Flag as inappropriate Answer (Will this adapter also support the older display port Apple displays on the video side?)

Yes, you can, according to Apple support document HT207266 "Connect devices and displays with the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter".

However, this is only useful for Thunderbolt networking (read Apple support document HT206909 "Networking two Mac systems directly with a Thunderbolt 3 cable requires Thunderbolt-enabled hosts") and Target Disk Mode (read Apple support document HT201462 "Use target disk mode to share files between two Mac computers").

The 2017 iMac does not support Target Display Mode (read Apple support document HT204592 "Use your iMac as a display with Target Display Mode") so you cannot use the 2017 iMac as a display for the MacBook Pro.

• Answered by Joseph V from Fort Langley
• 13/12/2017
• Flag as inappropriate Answer (does this work for connecting a 2015 macbook pro 13 retina to a 2017 5k imac?)

The Thunderbolt 3 to Thunderbolt 2 adapter does not pass DisplayPort signals. It can pass a Thunderbolt encoded DisplayPort stream over Thunderbolt to a Thunderbolt display, but the LG 43UD79-B is not a Thunderbolt display.

The LG 43UD79-B has a DisplayPort input that you can use instead. For the USB-C port, it may be possible to use a USB-C to DisplayPort cable (I think they're reversible) but you wouldn't be able to use the USB features of the display (which might include audio, unless audio is handled over DisplayPort).

For a display that has only a USB-C input, you can use a DisplayPort to USB-C converter. These don't exist, except as a PCIe card such as the Sunix UPD2018 or Delock 89582 for USB-C with DisplayPort alt mode. A Thunderbolt add-in card such as the GC-ALPINE RIDGE can also work to convert DisplayPort to USB-C with DisplayPort alt mode for USB-C displays, and can also convert DisplayPort and dual DisplayPort to Thunderbolt for Thunderbolt displays. PCIe cards require power from a PCIe slot, but the slot doesn't need to be connected to the same computer to support DisplayPort conversion. If you also want to use the other features of the cards (USB or Thunderbolt controller) then the card needs to be in a PCIe slot that is accessible by the computer. A Thunderbolt card must be placed in a PCIe slot that supports a Thunderbolt add-in card only if you want to use the USB controller or PCIe transmission over Thunderbolt. Conversion of DisplayPort to USB-C with DisplayPort alt mode or to Thunderbolt does not require a PCIe slot that supports Thunderbolt.

• Answered by Joseph V from Fort Langley
• 15/10/2017
• Flag as inappropriate Answer (If I connect this adapter to a USB-C port of LG 43UD79-B monitor (displayport over usb-c), can I use my Mac Pro 2013 (thunderbolt 2)?)

The MacBook has USB-C ports that only support USB, DisplayPort 1.2, and HDMI 1.4 (using passive adapters). Active adapters can convert DisplayPort to VGA, Dual Link DVI, and HDMI 2.0.

USB-C/Thunderbolt 3 devices may include a billboard USB device or USB Power Delivery (PD) information that can tell the computer what kind of device it is. This way, your MacBook can tell that the device is Thunderbolt 2 and give you that information that it won't work.

The Apple Thunderbolt 3 to Thunderbolt 2 adapter will work to connect Thunderbolt 2 devices/computers to Thunderbolt 3 devices/computers which includes the MacBook Pro, iMac, and your TB2 disks.

There is no way to connect a Thunderbolt device to a computer that doesn't have Thunderbolt.
There is no way to add Thunderbolt to a computer (unless it's a PC with Thunderbolt add-in card support).

What you can do is transfer the hard disk inside the TB2 disk to an enclosure that uses USB.
Or you can connect the TB2 disk to a computer with Thunderbolt, enable file sharing on that computer, and connect to that computer from your MacBook.

• Answered by Joseph V from Fort Langley
• 19/12/2017
• Flag as inappropriate Answer (Is there a way to connect an external TB2 disk to a new MacBook? When using this connector a warning: this MacBook doesn't support TB2 devices appears)