VirtualBox 5.1.28 fails to install on MacOS 10.13 due to KEXT security I have tried to install VirtualBox 5.1.28 to macOS high sierra but it fails every time with the following screen:


After some looking around I found this thread and I did indeed see that it was blocking VirtualBox from installing.



After clicking allow and then trying to run the VirtualBox installer again it just fails again with the same generic error message and the same Security warning reappears in the "Security and Privacy" settings.

I tried to also run the pkg install from the terminal to see if I could get more information about why its failing but it doesnt help.

➜  Documents sudo installer -verbose -pkg VirtualBox.pkg -target /
installer: Package name is Oracle VM VirtualBox
installer: Installing at base path /
installer: Preparing for installation….....
installer: Preparing the disk….....
installer: Preparing Oracle VM VirtualBox….....
installer: Waiting for other installations to complete….....
installer: Configuring the installation….....
installer:
#
installer: Writing files….....
#
installer: Writing files….....
#
installer: Optimizing system for installed software….....
#
installer: Running package scripts….....
#
installer: Running package scripts….....
#
installer: Running package scripts….....
#
installer: Running package scripts….....
#
installer: Running package scripts….....
#
installer: Running package scripts….....
installer: Validating packages….....
#
installer: The install failed (The Installer encountered an error that caused the installation to fail. Contact the software manufacturer for assistance.)


The VirtualBox application does appear to install and it can be launched however nothing functions.

Does anyone have any ideas how to solve this?
Managed to solve it.


Eject the VirtualBox image from: Finder > Devices


Now allow the exception in: System Preferences > Security &amp; Privacy


Finally but not least click Allow button so that way the developer with the name "Oracle America, Inc" will be accepted and the installer using that certificate will run just fine (basically this installer is signed using "Oracle America, Inc" certificate so we are required to enable it use on our machine first)
Then try to install from the .dmg again so that it remounts the device.


Now its working fine for me.