After a fresh install of Ubuntu 18.04 with pretty much all packages that I'd need, including virtualbox I encountered a problem. After trying to start a VM I got a familiar message saying that the kernel driver was not installed, thus either installing it or running the command 'modprobe vboxdrv' would fix the issue, which normally does.
However, this was not the case, and I was sure all dependencies were installed up to this point, including virtualbox-dkms. Upon running the modprobe vboxdrv command I encountered another message saying " modprobe: ERROR: could not insert 'vboxdrv': Required key not available"
See image below:
The reason for this was not so obvious, despite the fact that newer Ubuntu versions boot with EFI systems and Secure Boot enabled in the BIOS; this was the main cause.
Thus, in order to solve the issue I had to go into the BIOS and disable these settings, and finally the issue was solved.
published by Alberto J. Matus