The Apple Thunderbolt 3 to Thunderbolt 2 adaptor supports nothing except Target Disk Mode.
I tried using it to connect a USB-C SSD to my MacBook Pro 2014, using a Thundebolt 2 M-M wire, and the adaptor plugged into the SSD enclosure. It didn't work, though thankfully it didn't fry anything either.
The Thunderbolt adaptor also doesn't work with MiniDP-VGA or MiniDP-HDMI adaptors. So I would need to buy a whole new set of video adaptors if I upgrade my laptop. Needless to say, I'm not in a hurry to do so.
I like adaptors, and I have a large collection in my bag already for video out/in, phone charging, FireWire/Thunderbolt disk mode, and more. But I haven't even started collecting USB-C adaptors because it would only be for friends ("Sorry for the technical difficulties with the projector...") and I don't know which ones will work.
> The Apple Thunderbolt 3 to Thunderbolt 2 adaptor supports nothing except Target Disk Mode.
This isn’t correct. I use it daily to connect a MacBook Pro with Thunderbolt 2 ports to a RAID enclosure/dock with Thunderbolt 3 ports via a TB2 cable terminated with this adapter. An external monitor is attached to the enclosure, as well as several USB devices. The display port alternate mode signal and USB hub functionality all works simultaneously with the RAID.
Of course, half the problem with USB-C is that the failures are incredibly opaque, so it’s hard to say why the adapter failed in your case. Maybe you plugged it into a USB 3 USB-C port instead of a TB3 USB-C port? My enclosure has separate USB-C ports for each protocol, and I need to be careful to select the right one.
I tried using it to connect a USB-C SSD to my MacBook Pro 2014, using a Thundebolt 2 M-M wire, and the adaptor plugged into the SSD enclosure. It didn't work, though thankfully it didn't fry anything either.
The Thunderbolt adaptor also doesn't work with MiniDP-VGA or MiniDP-HDMI adaptors. So I would need to buy a whole new set of video adaptors if I upgrade my laptop. Needless to say, I'm not in a hurry to do so.
I like adaptors, and I have a large collection in my bag already for video out/in, phone charging, FireWire/Thunderbolt disk mode, and more. But I haven't even started collecting USB-C adaptors because it would only be for friends ("Sorry for the technical difficulties with the projector...") and I don't know which ones will work.