Since day one of owning the vive (from when they first came out) I have ALWAYS had issues with the whole system. Some times it works flawless as if no issues, then you can just turn it on one day and it struggles to detect base stations, or you get no audio or a blue screen on the headset even if you were only just using it the night before without issue this is no guarantee it will work the next day.
I think most of the faults are down to drivers/usb, but why they should fail especially if all you might have done is shut down the pc. For me the solution that often works is just inplug it from one usb port and put it in another (usb3/2 makes no real different, a possible scapegoat).
One of the biggest issues I have had since day one which can disappear for months but then return later with vengeance. If I press the menu button (one under the trackpad) the vive controller (any controller doesn't matter) locks up, the controllers will start flashing in SteamVR app and say "Controller disconnected", both base station icons turn grey but then 30 seconds later show online again. the headset turns blue. You have to wait 30 seconds or so, hold down the menu button on the joypad and then it connects again, and works right. This is issue is very random, I have never ever found a fix for it, USB2 possibly makes the issue happen even more.