I just had the exact same issue (originally by the OP)
after upgrading from 13.1 -> 13.2
What I understood - please correct me, if I'm wrong:
Some packages are not up-to-date, when a new FreeBSD version is released,
so you simply may wait some days, and do a
pkg upgrade
or install the package by ports instead.
So I did what I understood from the first couple of posts:
pkg remove virtualbox-ose-kmod
(which removes vb completely, of course)
Then
cd /usr/ports/emulators/virtualbox-ose/
make install clean
(more automatic: # yes | make ... )
and then
kldload vboxdrv
et voilà!
vb runs.
But first unload FreeBSD's bhyve kmod:
kldunload vmm
Don't know why, but as
scottro pointed out in his first post,
in conflicts with vb.
(I had the same issue since I've first started with vb on FreeBSD.
Took me a while to get this.)
Until I start to dig into bhyve while using vb only,
I like to have it not automatically loaded,
so I tried to unset it in /boot/loader.conf:
but it's still loaded
Something completely silly by me?