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Help with external usb c hard drive

B

brsboarder

macrumors 6502a
Original poster
Feb 16, 2004
763
15
So, I have a 2017 21" iMac.
I wanted to run it off an ssd and therefore bought a NVMe hard drive and put it into an external usb c case.
The hard drive shows up on my 2019 macbook pro, but won't show up when plugged into my imac.
The light on the drive shows up, but it doesn't show in disk utility or on the usb when I look at the system profile.

Any ideas? I tried my samsung t5 on the same usb and it shows up on the desktop, but under the hardware-thunderbolt system information it still doesn't show up
 
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What OS is on the iMac? What OS is on the MacBook Pro? What format did you use for the new drive? If you formatted APFS on the newer MacBook Pro, it wouldn’t show up on the iMac if the running an older OS.

The Samsung T5 isn’t a Thunderbolt device. It shouldn’t show up under Thunderbolt system information.
 
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Both computers running Catalina.
I switched the drive to see if it would run off the usb port using a usb c to usb 3 cord and it shows up on the mac when I switch the ports, but I can't run an OS off usb so the question is where is the problem, the thunderbolt port or the ssd or the case. I'm not sure how to triage.

I tried resetting pram and SMC
 
Perhaps we are talking in circles. You have a USB drive, so it must be connected to USB on the Mac. You can boot and run from USB devices. You might need an adapter to connect to the iMac.

Thunderbolt isn't even part of this discussion.
 
chabig said:
Perhaps we are talking in circles. You have a USB drive, so it must be connected to USB on the Mac. You can boot and run from USB devices. You might need an adapter to connect to the iMac.

Thunderbolt isn't even part of this discussion.
Click to expand...
Lets clarify. I have an iMac. It has both usb 3 and usb c (thunderbolt) ports if I am correct. I have an external drive that has a usb c port. I'd like to connect the external drive to my mac using usb c to usb c in the same way that I connect my samsung t5 usb c to usb c. When I use the wire from the samsung drive to this external enclosure, it doesn't read. When I use that same external drive, and that same wire and connect it to my macbook pro, it works.
 
OK. I understand perfectly now. Your Samsung T5 shows up on the iMac, but the generic external USB-C case (using the same cable) does not. That is weird for sure, and I can't think of any reason it wouldn't short of some incompatibility with the case.

So I think your easiest solution would be to connect the drive to one of your old-style USB-A ports using an adapter and just run it from there. The speed of data transfer is limited by the USB interface of the external case no matter which port you use, so the speed should be the same.
 
If your external case is supposed to support USB 3.1 gen 2 over USB-C port then you’ll miss out on the extra speed versus the USB-A 3.0 speed ports... But if it works then at least it works...
 
OP --

Try this.

Connect the "problem" USBc drive to the iMac.
I suggest you try the USBc port first, and answer the questions below.

Now, answer these questions:
1. Does the icon for the drive show on the desktop?
2. If you open Disk Utility, can you see the drive that way?

Now, disconnect the drive and RE-CONNECT IT using a USBa port on the iMac.
And answer the two questions again.

It could be...
- the blade drive itself
- firmware on the blade drive
- the blade drive's enclosure
- firmware on the enclosure
- the cable you're using
- a combination of factors
- something else.
 
Fishrrman said:
OP --

Try this.

Connect the "problem" USBc drive to the iMac.
I suggest you try the USBc port first, and answer the questions below.

Now, answer these questions:
1. Does the icon for the drive show on the desktop?
2. If you open Disk Utility, can you see the drive that way?

Now, disconnect the drive and RE-CONNECT IT using a USBa port on the iMac.
And answer the two questions again.

It could be...
- the blade drive itself
- firmware on the blade drive
- the blade drive's enclosure
- firmware on the enclosure
- the cable you're using
- a combination of factors
- something else.
Click to expand...
Im not sure how that helps. As I mentioned, the drive runs fine on USBa, but is not recognized on desktop or disk utility with USBc
 
"the drive runs fine on USBa, but is not recognized on desktop or disk utility with USBc"

Try a different ENCLOSURE.
See if that makes a difference.
 
@brsboarder what is your enclosure exactly? Is it a TB3 or USB3.x one? Was is connecting to you MacBook Pro as a TB3 device or a USB3 one?
 
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