If you've just installed VBox and it is not starting or working, the most common problem is usually that you don't have your kernel source installed, which means there is no kernel driver for vbox so it can't work.
So the first thing you should do is install your kernel source by running this:
sudo apt-get install linux-headers-`uname -r`
Then install the dkms/kernel module for vbox........
When using the .sh script the rendering doesn't work after an upgrade of related packages to kdenlive.
kdenlive (kdenlive:amd64 (4:17.04.1+git201705191233~ubuntu16.04.1)) with affine or composite transitions was fine but is now broken during the time of transition it is just a white screen.
The previous version was fine:
But now I can't find it or install it:........
The solution was to reinstall the vbox dkms package and do a manual modprobe of the modules it makes.
I never sorted out the unable to start due to the USB issue, I did have the guest additions installed but the only way to boot was to change the pointing device from USB to PS2 and then to disable the USB controller (if your pointing device is set as USB, disabling USB will not work because it will re-enable by default when it sees your pointing device is USB, this is w........