Hi,
Just a heads-up contribution:
After sysprep of a Win8.1 Pro box, Device Manager shows yellow "VirtualBox Host-Only Ethernet Adapter". Browsing to the inf doesn't fix it.
Please read these first for similar background:
viewtopic.php?f=6&t=37035#p166351
https://www.virtualbox.org/ticket/11948
Running a Repair of VBx doesn't fix it.
Can't re-attach the service to the NIC, because the service is absent from the NIC's Add dialog.
Adding dword MaxNumFilters doesn't help either.
Reinstalling Additions no help.
Only thing that works (and it's fast enough) is uninstall/reinstall VBx.
Btw, I experienced this using "VirtualBox - v5.1.8-111374-Win 64bit.exe" .
Hth.
Regards . . .