While listed as only for a 2.5 HDD, has anyone tested this on a Desktop 3.5 HDD?

This will not work on a 3.5 drive. The USB power supply is 5V. The 2.5 drives only use a 5V power rail, which is why this works on them. 3.5 drives have a 12V power rail, along with the 5V power rail. To run a 3.5 drive, you need an external 12V power supply. There are interfaces that come with it.

USB 3.0 to 2.5" SATA III Hard Drive Adapter Cable w/UASP ... Great! Is this thing USB 2.0 backward compatible in case I need it that way?

I've been able to use these with SSD's and USB 2.0. Usually laptop HDD's pull too much power to work on 2.0, and I've seen a couple older ones pull too much for 3.0. I work in a computer repair shop where we use these things like crazy, and it often depends on the drive you're using, and whether your USB port is able to push the power it's supposed to be rated for. Feels like a coin flip if you're working with a platter drive, but SSD's do fine.

2.5" drives don't require a power adaptor? All I need is this cable?

Yes. I had an SSD drive connected to the back of a server's USB 3 port for weeks without issue with no external power adapter.

Is this compatible with the Samsung Data Migration / Magician tools? They will not detect my drive with the other adapters I own.

I just ran into this issue with a Samsung 500 Gb 860 EVO SSD. The Samsung Magician Software did not see the SSD. There was a suggestion on one of Samsung's support sites (user community) that the bios settings for the HDD controller could be at fault. I checked mine and they were set to RAID (even though I don't have a RAID configuration). The recommended setting is AHCI. I changed it to AHCI (despite the warning that the computer might fail to boot) and rebooted. Rebooted without an issue, but Magician still didn't "recognize" the SSD as a Samsung "compatible" drive. I then downloaded Samsung Data Migration tool, which is really what you need for the cloning. IT WORKED. So as indicated elsewhere, there is some issue with certain combinations of Samsung software and the newer SSD's. I will try to remember to test it with an older USB 2.0 -> SATA adapter I've used in the past without issue. In the end, the cable worked as advertised.

Brand	StarTech
Connector Type	Sata/Usb
Cable Type	USB
Compatible Devices	Chromebook, Computer, Hard Drive, Laptop, SSD
Special Feature	Data Transfer
Compatible Phone Models	No Compatible Phone Models
Recommended Uses For Product	transferring data
Color	Black
Connector Gender	Male-to-Female
Data Transfer Rate	10 Gigabits Per Second
Shape	Round
Number of Pins	24
Frequency	10 GHz
Unit Count	1.0 Count
Item Weight	0.03 Kilograms
Model Name	USB 3.1 (10Gbps) Adapter Cable for 2.5" SATA Drives - USB-C
Specification Met	No
Indoor/Outdoor Usage	Indoor, Outdoor
Number of Items	1
Outer Material	Plastic
Manufacturer	StarTech.com
UPC	065030863032
Global Trade Identification Number	00065030863032
Standing screen display size	2.5 Inches
Item model number	USB31CSAT3CB
Item Weight	1.03 ounces
Product Dimensions	20 x 1.7 x 0.2 inches
Item Dimensions LxWxH	20 x 1.7 x 0.2 inches
ASIN	B0133F30R8
Is Discontinued By Manufacturer	No
Date First Available	August 27, 2015

StarTech.com USB C to SATA Adapter - External Hard Drive Connector for 2.5'' SATA Drives - SATA SSD / HDD to USB C Cable (USB31CSAT3CB) Black

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