Vagrant not launching VM

I have an issue with Vagrant launching JunOS Olive images, please see error output below after a 'vagrant up'. Any ideas?

There was an error while executing VBoxManage, a CLI used by Vagrant for controlling VirtualBox. The command and stderr is shown below.

Command: ["startvm", "07576ae9-79a9-4b80-94ac-af1fab293d73", "--type", "headless"]

Stderr: VBoxManage: error: NamedPipe#0 failed to bind to local socket \.\pipe\gns3_vbox\a6fc3ef7-520b-4052-beeb-65db1f798b22 (VERR_WRITE_PROTECT) VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component ConsoleWrap, interface IConsole

I think you are using a Mac since the exact same problem came up for me when I installed Vagrant for the first time and tried to launch a box. As you probably already know, Vagrant uses some 3rd party virtualization software (e.g. VirtualBox or VMWare), so I opened up VirtualBox and tried to start the VM manually when I got this error message:

Somehow, despite having already installed VirtualBox successfully without any errors beforehand, the Kernel driver was said to be not installed. This must mean that the OS was rejecting it. Therefore, I proceeded to go to System Preferences:

And then to "Network and Security", where I found a small dialog box asking for permission to run the software:

After allowing the software and re-running vagrant up, it started working properly.