linux-image-4.15.0-34-generic under VirtualBox does not boot

linux-image-4.15.0-29-generic luckily works, still.

With the -34, the system hangs at boot, all other settings being the same.

Running on host system OSX 10.13.6 on a 2.6GHz i7 (MacBookPro15,1).

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-34-generic 4.15.0-34.37
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.3
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ehaase 2561 F.... pulseaudio
CurrentDesktop: KDE
Date: Mon Sep 24 15:15:47 2018
InstallationDate: Installed on 2017-04-27 (515 days ago)
InstallationMedia: Kubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
IwConfig:
 docker0 no wireless extensions.

 enp0s3 no wireless extensions.

 lo no wireless extensions.
Lsusb:
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
 Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
MachineType: innotek GmbH VirtualBox
ProcFB: 0 vboxdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-29-generic root=UUID=2b0c0d65-6797-47cc-ac98-ea184260ce95 ro quiet splash
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-29-generic N/A
 linux-backports-modules-4.15.0-29-generic N/A
 linux-firmware 1.173.1
RfKill:

SourcePackage: linux
StagingDrivers: vboxvideo
UpgradeStatus: Upgraded to bionic on 2018-05-22 (124 days ago)
dmi.bios.date: 12/01/2006
dmi.bios.vendor: innotek GmbH
dmi.bios.version: VirtualBox
dmi.board.name: VirtualBox
dmi.board.vendor: Oracle Corporation
dmi.board.version: 1.2
dmi.chassis.type: 1
dmi.chassis.vendor: Oracle Corporation
dmi.modalias: dmi:bvninnotekGmbH:bvrVirtualBox:bd12/01/2006:svninnotekGmbH:pnVirtualBox:pvr1.2:rvnOracleCorporation:rnVirtualBox:rvr1.2:cvnOracleCorporation:ct1:cvr:
dmi.product.family: Virtual Machine
dmi.product.name: VirtualBox
dmi.product.version: 1.2
dmi.sys.vendor: innotek GmbH