Created attachment 863110 [details]
/var/log/virtualbox.log

Symptoms are similar to those reported in Bug 1204331.  

https://bugzilla.opensuse.org/show_bug.cgi?id=1204331

When I start either of two USB scanners in the Win 7 client, I get the Windows
error:

* * *

One of the USB devices attached to this computer has malfunctioned, and Windows
does not recognize it.

The location of the device is shown in bold type.

* USB Root hub (12 ports)
 - Unknown Device

* * *

As it may help in troubleshooting, I'd better mention that the 6.1.38 bug
referred to in:

https://forums.opensuse.org/showthread.php/576712-VirtualBox-with-enabled-USB-NS_ERROR_FAILURE-(0x80004005)/page2 

was not present with 6.1.38 in kubuntu.  In kubuntu, 6.1.38 passthrough worked
fine.  

I need to use these scanners, so have restored an earlier snapshot and locked
virtualbox files at version 6.1.40.