I have the exact same problem with an Ultrafit 64GB. Is not detected (device manager or disk management) in any USB 3.0 port (Windows 10 Pro) but is in USB 2.0 ports (on colleagues computer). I even tried a different USB 3.0 port on a different computer, no go. It also gets REALLY hot.
I contacted customer support for RMA…am waiting for the email.
I’m having the same issue, actually twice. When I originally received 3 of the 128G, about a year ago, they worked fine for about 6 months. Then they started overheating (VERY hot) and slowing down. I returned them to SanDisk under warranty and received new ones. Those were fine for a bout 6 months and now, I’m back in the same situation. They are overheating and have slowed down so much as to be unusable.
There seems to be a design flaw with these 128G units. I have several 64 Gig ones of the “same model” and those have been working fine for years.
Does anyone know if SanDisk will replace these with a model that works? If they sent me replacement of the same model, I would not trust them. I keep good backups, but every time they fail, I have to go through recovering everything and that is time consuming.
The return process seems so “sterile”. I’m afraid if I return these under warranty, I’ll just get more of the same. Any thoughts?