The developer team identifier or KEXT of the install is not trusted by the operating system. There’s no way to allow an exception through the regular interfaces for the installer to successfully run. One must manually add the developer team identifier so that it can run. This is done in recovery mode. Unless you’re a developer used to hacking your Mac to allow things like this to happen, you’d never get it done.
Many thanks to “rayan a” for providing the solution:
https://forums.virtualbox.org/viewtopic.php?f=8&t=89769
Re: Unable to run on Mojave
by ryan a » 29. Jan 2019, 21:33I was able to get the kernel extensions to load the KEXTs without user approval by adding the VirtualBox Apple Developer Team ID in spctl kext-consent
I used the following command to get the Team ID: codesign -dv --verbose=4 /Applications/VirtualBox.app
Result: TeamIdentifier=VB5E2TV963
- Turn on your Mac, then immediately press and hold Command-R to start up from macOS Recovery.
- Select Disk Utility from the Utilities window, then click Continue.
- From the Disk Utility sidebar, select the volume that you’re using, then choose File > Mount from the menu bar. (If the volume is already mounted, this option is dimmed.)
- Then enter your administrator password when prompted.
- Quit Disk Utility.
- Choose Terminal from the Utilities menu in the menu bar.
- Type the command:
spctl kext-consent add VB5E2TV963 - When done, choose Apple () menu > Restart.