Windows 10 Cannot use USB flash drive after upgrade to Windows 10

drosso

TS Rookie
Hi,
I've just upgraded from 7 to 10; upgrade was smooth and everything seemed to work as expected until I tried to read a USB flash drive.
When I insert a USB drive nothing happens, the drive is not visible and a yellow triangle with the exclamation mark is shown in device management window.
All other USB devices work (Keybord, Mouse, Xbox controller, Canon camera, Tom Tom navigator) but USB drives are unusable.
I've already tried many times to uninstall and reinstall the driver, but nothing changes.
The only thing I have not yet done (and I'm not too keen on doing, as I would not want to loose also keyboard and mouse) is to uninstall all USB drivers and let Windows 10 install them when rebooting the system.
I would try to install the drivers manually, but I don't know where to download them
Any idea on how to fix this problem ?
Thanks in advance.