USB device is captured but not available

[justus]

Host system: Solaris 11.1
Concerns guests: Ubuntu 12.04, Windows 7, Linux Mint, FreeBSD (i.e. all my guests).
Concerns versions: VB 4.1.6 (at least) ... VB 4.3.8 (currently running).
Issue: The Devices Menu in the guest shows keyboard, mouse, and (if plugged in) the USB device.
When I check the USB device, it is indeed captured (icon disappears on host). Unchecking is also possible (icon re-appears on host). But the USB device is never accessible on the guest (no icon appears, and e.g. on the Ubuntu guest, there is no entry in /media).
Of course: Extensions installed on host, newest Additions installed on guest, user (me) in group "vboxuser" on host. Btw.: On Linux hosts this group would be called "vboxusers", why that difference? See http://www.virtualbox.org/manual/ch02.html.
No corresponding message in logs.

Any ideas, why this behavior started in VB 4.1.6 (maybe also in some earlier version)?
Any solution or workaround?

[Ramshankar]

See this thread: viewtopic.php?f=11&t=55816&start=30

[justus]

Great!
The link to the alternative driver, posted on 31. Jan 2014 - 16:09 in that thread, finally solved the problem, at least for Ubuntu 12.04 (did not already test all the other guests).
Here is another hint: After booting the host from init 5, the virtual machine recognized the USB device, but could not use it, which was notified by an error pop-up in the guest. Solution:
# touch /reconfigure
# init 5
Reboot the host.

Thanks
Norbert