I've done update installs of W10 on 2 of my computers, no problems at all. I then tried it with my latest built computer which went a little differently and wound up not having a (usb) mouse or usb working. When I was installing W10 from a usb stick there popped up a message box I'd not seen with the other 2 installs: something like, please remove the usb stick and do you want an update install or a clean install (again, this was after the installation had started up). I removed the stick and said yes for the update install. So in the end finding the mouse not working I checked the device manager and all the usbs had a yellow '!'s saying "the software for this device has been blocked because it is known to have problems with Windows[code 48]. I tried updating the drivers but it said the drivers are the latest. I tried troubleshooting the drivers and all I got was churning as it was looking for whatever. I gave up after a few hours and returned to W7 where thankfully the mouse and usb ports are working and everything seems ok. In the device manager however while most of the usb devices are ok, under other devices there are 3 usb controllers with a yellow ! listed which say pci bus 4, other device, unkown. I just have no memory of seeing whether these were ever connected or ok. So I guess the question is why this happened in this case and should I try doing the upgrade install (much preferred) again.