[ 12.327] (II) Loading /usr/lib/xorg/modules/drivers/vboxvideo_drv.so
[ 12.327] (II) Module vboxvideo: vendor="Oracle Corporation"
[ 12.327] compiled for 10.15.0, module version = 1.0.1
[ 12.328] Module class: X.Org Video Driver
[ 12.328] ABI class: X.Org Video Driver, version 15.0
[ 12.328] (EE) module ABI major version (15) doesn't match the server's version (18)
The virtualbox driver isn't loading, and it looks like you dont have virtualbox 4.3.14-dfsg-1build1 which is the one that works with it. Is the update available to you?
[ 12.327] (II) Loading /usr/lib/ xorg/modules/ drivers/ vboxvideo_ drv.so
[ 12.327] (II) Module vboxvideo: vendor="Oracle Corporation"
[ 12.327] compiled for 10.15.0, module version = 1.0.1
[ 12.328] Module class: X.Org Video Driver
[ 12.328] ABI class: X.Org Video Driver, version 15.0
[ 12.328] (EE) module ABI major version (15) doesn't match the server's version (18)
The virtualbox driver isn't loading, and it looks like you dont have virtualbox 4.3.14-dfsg-1build1 which is the one that works with it. Is the update available to you?