Can't use an USB device in Windows 10 guest: "is in use by someone else"

[DKroot]

I'm running Windows 10 guest on OS X El Capitan host.

I can't ever pass USB smart cart reader to the guest using the status bar icon because of the following error:

Failed to attach the USB device SCM Microsystems Inc. SCR3310 v2.0 USB SC Reader [0204] to the virtual machine Boot Camp.

USB device 'SCM Microsystems Inc. SCR3310 v2.0 USB SC Reader' with UUID {34262c72-da4e-4d08-99ff-ca2bee575214} is in use by someone else.

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: HostUSBDeviceWrap
Interface: IHostUSBDevice {c19073dd-cc7b-431b-98b2-951fda8eab89}
Callee: IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

The USB device in question is not really in use other than being plugged in.

Things I tried so far:

1. Create and use an USB filter
2. Switch between USB 2 and USB 3 in VM settings.

This is a critical issue for me, because I need to use VPN for work and I can't use the host VPN either because of VM crash in NAT mode (a separate issue).

[DKroot]

Log from the running VM

[mihail.izhevskij]

Adding my case description here as it seems to be the same issue.

Macbook Pro A1398, Host OS: MacOS Sierra, Guest OS: Windows 7 64x

I want to use USB Osciloscope Instrustar ISDS2062B, it requires USB2 and Windows OS. After installing and plugging in the device the message is given: "Other Software Uses Device". It's being done with latest VB Extension Pack and Guest Additions installed. Seems like Client OS just doesn't get full access to that device. Tried switching to USB1 and USB3 and setting filters, didn't help.

Not to criticize anybody or compare, tried exactly same software installation in Parallels virtualization, worked flawlessly.

[Socratis]

May I suggest something? It's usually better and faster, if problems like this one (configuration, question) get first addressed in the forums (​https://forums.virtualbox.org/). More than 95% of the issues are resolved over there, which keeps the developers focusing on the bug fixes and enhancements, and there is no need for another ticket to keep track of. For example, yours is most probably not a bug and someone from the developers has to deal with it and close it as "Invalid".

So, if you can, please open a new thread in the ​VirtualBox on Mac OS X Hosts section of the forums. Be sure to say that you came from the bugtracker and include the ticket #.