Does it not show up in Disk Utility either? If it shows up there it’s just not mounted. No idea why that would be though. Never seen anything like that myself.
Should be much faster than a regular cheap stick. You can get something like Blackmagic Disk Speed Test for free on the App Store if you want to check. This SSD should be giving you something like ~400 MB/s. My old sticks do maybe 25 MB/s.
Forgot Disk Utility! I just left it for over an hour opened to a VM - both machines went to sleep and it woke up ok. I usually don’t keep drives plugged into this machine, and I rarely reboot, so maybe the issue has been there all along.
I actually bought a drive dock from OWC over Thanksgiving so I’ll try it in there too.
I can say it’s way faster than the original drive from my 2008 unibody that I used for TurboTax over the summer. That was a “boot and take a nap” drive!
Thanks for your help!
Diane
Even more interesting… I setup the dock, rebooted the laptop, and it selected the drive in the dock as a boot drive. (the Kingston)
I rebooted a few times and that was fine.
I reset the startup disk to the internal drive, and I can see the Kingston on every reboot now. So it’s something in the external case or the cable they sent, and I’m not sure I have another cable like that to experiment with. I will request a swap on that and use the drive in the dock until then. 
Plus now that I opened the dock box, I can start the project of going through drives I keep finding =:0
Diane
Yeah, if you can confirm this is cable or case related, I would ask for a replacement. If it fails again, go with another make.