Not sure if my USB 3 ports on my motherboard are dead or what, although it seems like they might be. I have an external USB 3 HDD that I keep connected to my PC. Sometime while I was asleep it no longer showed up on my PC. I've tried everything I can think of. I've restarted Windows 10 RS5, tried all 4 USB 3.0 ports, tried my other 2 external HDDs & Flash drive, checked Device Manager (nothing shows up), checked Devices in Settings (nothing shows up), and even booted into gParted Live CD to see if it was just Windows and still nothing shows up. All the drives work as they connect just fine using my USB 2 ports. What's odd is that the drives when plugged into the USB 3 ports kick on & the enclosure light goes on. Worst case scenario if they're dead is I spend the 25-35$ and just get a PCI-E card, so not that horrible.
Yep, checked all that as well. USB 3 is enabled, XHCI is Enabled, powersaving stuff is off, etc. Was working fine last night before I went to sleep and I didn't change anything when I woke up as I noticed right away my drive wasn't being detected.
Try re-installing USB 3.0 drivers. (And a good defrag if it's a mechanical drive). Hopefully it's as simple as your drivers got corrupted. Good wishes.