Well, it took four tries, but success counts for something...
Enclosure is a new Thermaltake ST0020U, with an old Seagate Sata II formatted MBT NTFS nominal 2TB HD. Bought a pair just after the Thailand flood before the price hike, so you know this is an old drive. Wanted an enclosure with a fan (this has two) that I could leave on 24/7, and the older Rosewill combo esata/USB 3.0 wouldn't mount. Two different docking stations didn't mount either. One 2.5inch Sabrent would mount sometimes, but freak out and refuse to disconnect. Huh?
Anyway, firmware is current for now - 1.30-0.85 - on the LS421DE. Dismount works fine, and mounting goes smoothly so far. Expect if I put a different drive in the box it would work too. Box says it will work with Sata III at full speed, up to 3TB. Read and Write via the connection to the rest of the home network is just north of 40MB/s.
Attachment shows this really works. Anyway, I was starting to think the USB 3.0 was useless for me unless I bought a Buffalo USB External, but happy to report this is not the case. This enclosure is a little pricey but not ridiculous. It meets the need. It even works on my A*S*U*S RT-AC56U router on the USB 3.0, so whatever chipset this thing uses is probably the charm right now with firmwares being used.
Hope this helps others struggling with the USB 3.0 recognition issue out there. TTFN...
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