Hi, On Dom, 2014-08-03 at 15:01 +0200, Bruno Taglienti wrote: > I updated VirtualBox from the repository to 4.3.14. (Fedora 20) > It happens that no USB device is available to guest > operating systems. > Downgrading to 4.3.12 solves the problem. I finish my tests and the bug is already reported upstream https://www.virtualbox.org/ticket/13085 I build a new kernel with patch mention on #comment:13 and all works fine, so the problem is with kernels > 3.14 . So will take time to fix land into Fedora stable. I'm going try accelerate the process. When I receive your email I tried out a usb pen and doesn't work , after I go to VirtualBox -> main menu -> help -> check for updates , and install new Oracle Vm VirtualBox extensions 4.3.14 , and usb start to work, but kernel on host oops every to 2 seconds , without patch applied ...