[NAME] I would leave USB PowerShare disabled if don't need the USB ports to be powered when the PC is off, for example, if you have an external USB drive connected permanently to a USB port. I have encountered this situation where it seems that the USB port has shut down and only rebooting or powering off the system will restore it. I think that happens if a USB device connected to the port draws too much power. The solution I found that seems to work is to use a powered USB hub and not depend upon power from the PC's USB port. I think an external powered USB hub has the added benefit of protecting the PC's USB port from damage. 
I have had my Dell XPS 8950 about a week or so and have a problem of which USB ports to use. I have three external drives and a keyboard which require USB connections. I had both USB 3.2 and both 2.0 ports being used for all four devices. Today I got an error message telling me the device in the bottom left USB 2 port wasn't recognized so moved that device to next USB 2 port and is working okay. But when I try to plug in another drive, it doesn't recognize it and if I try the keyboard it lights up but fails to see any typing and I then get the same error message. Is there a fault with the port, I thought the USB 2 ports were just linked together? Can someone explain what is meant by smart power and power share? Which ports should I use, never had to think about this in older PCs? Thanks in advance for any replies.
XPS 8950, rear panel USB port options