virtualbox.org

running windows 10 client for a long time without problem until the recent auto updates to build 16299.98
windows 8.1 Build 9600 host is running virtual box 5.1.22 and has no problem with other windows client.
network discovery seems to be turned off despite it it set to to on

Re-install the Guest Additions in your Win10 client. You should be doing this every time that there's a major update to Windows. You can thank Microsoft for that...

Moving to "Windows Guests" from "Windows Hosts", since the problem seems to be with your guest.

thanks for the quick reply. re-install vmaddition resolves the problem
thx again

Great, thanks for the feedback. Marking as [Solved].