Cannot figure out how to enable UASP for external SSD transfer

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Level 1

9 points

Cannot figure out how to enable UASP for external SSD transfer

So I just got off the phone with Apple technical support and this issue seems to have them totally stumped. Here are the specs for my computer, as well as the external drive:

____________________________________________________________________________________

15" MacBook Pro (2017) / 2.8 GHz Intel Core i7 / 16GB 2133 MHz LPDDR3 / Radeon Pro 555 2GB / 1TB SSD

^ running macOS Mojave 10.14.6

Samsung T5 1TB External SSD / USB-C to USB-C cable

____________________________________________________________________________________

When purchasing this Samsung SSD, it promised "transfer speeds of up to 540 MB/s" so long as "the host device and connection cables must support USB 3.1 Gen 2 and the UASP mode must be enabled".

My goal is to try and achieve these transfer speeds while using this drive as a Time Machine backup. After many, many searches online, I was not able to find any instruction on how to enable UASP mode. All that I could find was instruction on how to determine whether or not my computer was capable of utilizing UASP. Those instructions said to navigate to

 > About This Mac > System Report > Software > Extensions

and look for "IOUSBAttachedSCSI," which appears in my list of extensions, but currently says "No" under the "Loaded" column.

I also found one thread on here where a user stated: "If I set the drive to APFS, UASP works. Before it was exFAT. So okay, Apple just supports their own stuff....but the big question is, why does UASP not work with my HFS Time Machine drive? Question to the Apple Team: why do you not support UASP on other filesystems than APFS?"

As Time Machine does not support writing to APFS-formatted drives, this doesn't really help me. Anyway, I'm wondering if anyone has any insight on this particular topic? I was amazed that after speaking with multiple people at Apple support, they were all at a loss.

MacBook Pro 15″, macOS 10.14

Posted on Jul 13, 2020 3:42 PM

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Answer 1

Jul 21, 2020 9:57 AM in response to mpepino

Ok, I was finally able to check my Mac at work where I have a UASP hub & drive dock (aka toaster) which are two separate devices. Before trying anything I checked the System Profiler and the UASP driver/extension was not loaded. When I put a drive in the drive dock and applied power to the drive dock macOS automatically loaded the UASP driver/extension (I had to refresh the System Profiler view by using Command + R so it checked the drivers/extensions again before the change could be seen).

Tested with a 2014 Mac Mini and macOS 10.10 Yosemite.

So if your system isn't automatically loading the UASP driver, then either some component in the chain doesn't support USB3 UASP protocol or one of the devices or cables is defective. Or perhaps you have some software issue either with macOS or some third party app/driver such as anti-virus, cleaning app, or third party security software none of which are needed on a Mac as they can interfere with the proper operation of macOS. Or maybe you've discovered a bug in macOS. Try testing everything by performing a clean install by erasing the drive before installing macOS. Test everything without migrating or restoring from a backup. You can install macOS to an external drive to test things if you don't want to touch your main boot drive.

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Answer 2

Jul 13, 2020 9:08 PM in response to mpepino

UASP support should be automatically enabled as long as the entire chain contains UASP supported components. If you are using a USB hub, then the hub must support UASP. If you are using any adapters/dongles, then they may also need to support UASP. Plug your USB drive directly into the Mac without using any adapters/dongles or hubs.

I don't think macOS loads the driver until you actually connect the UASP drive. Plus you need to refresh the System Profiler (or relaunch it) as it does not automatically update the system settings.

Maybe try rebooting the computer while your UASP supported drive is attached.

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Answer 3

mpepino Author

Level 1

9 points

Jul 15, 2020 5:22 PM in response to HWTech

Appreciate the reply! I'm plugging the Samsung T5 directly into the Mac, using the USB-C cable that came with the Samsung T5. I tried both refreshing System Profiler with the drive connected, as well as rebooting the computer with the drive connected, and under "IOUSBAttachedSCSI" still show "No" under the "Loaded" column.

Based on the transfer speeds that I encountered during a Time Machine backup yesterday, I'm almost positive that UASP was not automatically enabled.

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Answer 4

Jul 15, 2020 8:30 PM in response to mpepino

I'll see if I can test UASP on my Mac. I'm not sure I have what I need at home. I remember it just worked when I got my first USB3 UASP hub & adapters, but that was 6 years ago so I forget the details. IIRC it just automatically loaded the driver when a UASP drive was attached. I know I was using macOS 10.10 at the time.

FYI, You are not guaranteed full speeds for the SSD. SSD write speeds can become slow after just 30 or 40 seconds of writing data to an SSD when the SSD's write cache becomes filled. Some SSD write speeds can drop to 50% or more.

With UASP you probably won't notice any difference with just a single drive. UASP makes more of a difference when you are accessing multiple USB drives each with UASP support. Plus UASP also helps to keep older & slower USB 2/1 devices from slowing down the transfers of UASP USB3 drives.

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Answer 5

mpepino Author

Level 1

9 points

Jul 15, 2020 8:44 PM in response to HWTech

Totally understood and again, appreciate your reply! I freshly wiped and reformatted the T5 (as HFS+) and to give you an idea of the speed I got, it took roughly 11 hours for 910 GB of data (via Time Machine).

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Cannot figure out how to enable UASP for external SSD transfer

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