So I'm now on kernel 4.13 after the update of -hwe kernel from 4.10, and my vbox 5.1.30 (from the official virtualbox.org repo) runs fine on this host. Apparently, only 5.0.40, which is in Xenial repos, has this problem.
So I'm now on kernel 4.13 after the update of -hwe kernel from 4.10, and my vbox 5.1.30 (from the official virtualbox.org repo) runs fine on this host. Apparently, only 5.0.40, which is in Xenial repos, has this problem.