Let me illustrate my question.

I am using MacBook Pro Retina 15-inch (Mid, 2015) running macOS Catalina 10.15 Beta (19A558d).

Recently, I would like to use a SSD USB device as a external hard disk (512GB) to use Windows To Go and store other files.

I bought the SSD USB device with type-c port because I have other type-c devices, but the MacBook Pro for 2015 only has type-a USB port. Therefore, I also bought a type-c to type-a adapter.

Basically, I suppose I just need to make the USB SSD connected to the adapter, and the adapter connected to my MacBook Pro, and everthing will be settled. However, the MacBook Pro (connected to power adapter and is charged) does not recognized my USB devices, not in Disk Utility, not in BootCamp Windows, not in System Report, not in everywhere. What's more, the light on USB device is not blinking, which might infer that the device has not power.

I tested the SSD USB devices on my phone (which has a USB type-c port), and it will be recognized very well, and the light is blinking.

Therefore, I suppose the type-c to type-a adapter is broken and will not work. However, I connect the type-c to type-a adapter to my Surface Pro 6, and everthing works pretty well again, I can read and write the SSD and the light works well.

In the meantime, I connect another type-c USB device (32 GB) to the adapter, and connect them on my MacBook Pro, and everything just works fine...

Consequently, I think if the MacBook Pro is not giving enough power to the USB devices to boot them? The 32 GB device works pretty well and the 512 GB one will not work...

Anyone has suggestions please help me, thank you so much.

P.S. I found a similar question here.