id summary reporter owner description type status component version resolution keywords cc guest host 15956 USB Regression - Can't connect ST-Link/V2 JTag pod to Windows 7 Guest => fixed in SVN/next maintenance mkurtzsd "I recently updated my VBox installation from 5.0.8 to 5.1.6 and can no longer connect my ST-Link/V2 JTag debugging device to VirtualBox. The device is recognized and appears in the Devices | USB menu. When I click on the entry to attach it to my guest, I get the following error: {{{ Failed to attach the USB device STMicroelectronics STM32 STLink [0100] to the virtual machine Windows 7 (64-bit). USB device 'STMicroelectronics STM32 STLink' with UUID {2a4ef47b-5431-4540-8a60-c48d2ed4593f} is busy with a previous request. Please try again later. Result Code: NS_ERROR_INVALID_ARG (0x80070057) Component: HostUSBDeviceWrap Interface: IHostUSBDevice {c19073dd-cc7b-431b-98b2-951fda8eab89} Callee: IConsole {872da645-4a9b-1727-bee2-5585105b9eed} }}} I have ensured that the 5.1.6 Extension Pack is installed, the Guest Additions are installed, I have deleted everything but the Name, Vendor ID, Product ID settings with the Remote selection set to ""No"" in the USB port settings for the device with no success. I have booted the Windows guest with and without the USB device connected (connecting after boot when booted without the device connected) and have the same issue. I have also tried setting the USB support to 1.1, 2.0, and 3.0 in the Ports | USB settings dialog. If I uninstall VBox 5.1.6 and revert to v5.0.8 then the ST-Link will connect again. v5.0.8 is the last version that I have been able to get a connection with. I tried 5.0.26 and that didn't work either. I have a Windows 7 (64-bit) guest on OS/X. I am running Mac OS/X v10.11.6 on a MacBook Pro (Retina, 15-inch, Late 2013)." defect closed USB VirtualBox 5.1.6 fixed STLink,64-bit,USB Windows Mac OS X