You'll need to follow these steps to grant your approval: Unfortuantely, if you miss seeing that alert the first time it is shown, it is never displayed again. When you run the VirtualBox installer, macOS is supposed to show a warning message as shown here: Unfortuantely, like much of Apple's recent security theater improvements, the process to grant your approval is not straight forward.

To help with this, in recent verisons of macOS (beginning with High Sierra), Apple requires you to explicitly approve new kexts before they can run. This allows the app to hook into the lowest levels of macOS and do the magic necessary to run virtual machines on your system.īecause kernel extensions have such deep access into your Mac's system, you have to make sure you're only installing them from trustworthy developers. In order for VirtualBox to work, their installation program needs to install something called a ' kernel extension' (or 'kext') on your Mac. This allows us to run a web server on your Mac that works exactly like the 'real' web server you eventually upload your websites to. Ubuntu is a popular operating system used to power millions of web servers around the world. VirtualHostX uses VirtualBox to install and run an Ubuntu Linux operating system on your Mac.

A virtual machine is completely independent computer that runs inside your Mac. VirtualBox is 3rd party, open-source software developed by Oracle that allows you to run 'virtual machines' on your Mac.

Oracle virtualbox mac os