External SSD not working with USB C to A cable

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I have a cheap Sabrent SATA III to USB 3.0 SSD enclosure (EC-UASP, 2.5-Inch SATA to USB 3.0 Tool-free External Hard Drive Enclosure) that I often use with an equally cheap SSD for some extra storage. The device works well with all of my USB A ports (it comes with a very thick USB A to A cable) but today when I tried using it with a USB A to C cable to connect it to one of my laptop's USB C ports I found that the device doesn't even power on.

I tried another cable and even tried using the SSD with my phone instead of my laptop, but no matter what, the device simply won't turn on when connected to a USB C port.

From what I understand, a USB A device should be usable with a USB C port provided it is used with an adapter. I don't have a USB-C hub that would offer USB-A ports, so I can't test it with it's own USB cable.

The enclosure (with the SSD in it) seems to draw ~50mA at idle and maxes out at ~300mA when writing sequential data, so current draw shouldn't be the problem.

Image of the Sabrent enclosure from their official website that shows connections.

Best Answer

The device works well with all of my USB A ports (it comes with a very thick USB A to A cable)

That's one classic issue with the type-A port used on a USB device. Type-A ports are designated for USB hosts. You were using illegal A-A cables to connect it. Fine.

Now you are using a Type-A to Type-C cable. This cable is designed to connect USB host (type-A) to Type-C device. Therefore it has HOST SIGNATURE on CC pins in the cable's overmold. Your new Type-C is also a host, so you are attempting a host-host connection, and this fails for obvious reason.

To get your SSD enclosure to work with Type-C host, you need a Type-C to Type-A Female adapter, aka "OTG adapter.

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This adapter will have DEVICE signature on Type-C end, and FEMALE Type-A port, which will act just as an ordinary PC port. Then use your illegal A-A cable.

There is no single-piece Type-C cable which will connect your illegal device with Type-C port, unless you do a serious overmold "surgery" and switch the embedded pull-up to a 5.1k pull down on one of CC pins.