VirtualBox and Mountain Lion (Mac OS X 10.8)


VirtualBox 4.1.20 and later are now completely compatible with Mountain Lion and this jiggery-pokery is no longer needed

- FB]

Apple released Mountain Lion (Mac OS X 10.8) late last week and a few people are stumbling over installing VirtualBox on it, so here are a few tips:

At the time of writing, the current version of VirtualBox is 4.1.18. Strictly speaking, this is not commercially supported, but VirtualBox users tend to be an intrepid and gung-ho bunch, and will try to run it on Mountain Lion anyway. They'll download VirtualBox and run the installer by clicking on the VirtualBox.mpkg icon:

...and get a message like this:

This will happen if you are using the default Security settings of Mountain Lion for downloaded applications, which probably look like this:

Application Settings

To get VirtualBox installed you can either:

  1. temporarily allow applications downloaded from Anywhere in the System Preferences box above, changing it back after installation; or
  2. hold Control key down as you click the .mpkg and choose Open. Doing this, you'll get a subtlety different dialog like this:

...which now has an Open button. Clicking on this will get VirtualBox installed too.

HTH someone out there.


 P.S. You can expect to see a "Fully Supported" version in the not too distant future ;-)


Thanks a lot for the info! It works for me! I have installed VirtualBox 4.1.18 on Mountain Lion with these recommendations.

Posted by @jarmvel on August 07, 2012 at 07:20 AM BST #

Seems like Virtual Box got some bugs that cannot run stable on Mountain Lion ;P

Posted by guest on August 07, 2012 at 08:43 AM BST #

The installer failed for me, even after following above steps...

Posted by guest on August 11, 2012 at 07:10 PM BST #

Thank you!

Posted by Peter on August 12, 2012 at 10:22 AM BST #

Not an option. There was plenty of time, 12 + months, to get the certificates. Glad we dont rely on this VM Solution.

Posted by Helge on August 14, 2012 at 05:41 PM BST #

I was able to install windows XP as a guest OS on mountain lion but my XP guest is not able to connect to the internet. Host OS is able to connect using Airport...please help

Posted by Tanay on August 18, 2012 at 06:34 PM BST #

VirtualBox 4.1.20 makes this blog redundant.
Phew! ;-)

Posted by Fat Bloke on August 21, 2012 at 10:09 AM BST #

I disagree with you Fat Bloke... I cannot open or import any VMs as it locks up VB completely and I get the beachball... I'm on ML 10.8.0. Any ideas? I have disabled application restrictions completely.

Posted by guest on August 23, 2012 at 07:14 AM BST #


Upgrade to 4.1.20 or later if you can.
If not, get help at


Posted by Fat Bloke on August 23, 2012 at 11:01 AM BST #

Just tried to install 4.2.10 - install failed - now downloading new OS X update to 10.8.1 - we'll see what that does...

Posted by Glenn Dixon on August 26, 2012 at 07:27 PM BST #

Yep, the OS X update fixed it (or maybe rebooting fixed it?)

Posted by Glenn Dixon on August 26, 2012 at 07:36 PM BST #

I am running VirtualBox 4.1.20 r80170 on OSX 10.8 and although my images run, I don't think 4.1.20 is completely stable. . .

I have forced an OSX reboot multiple times this morning. I have three images (two RHEL 5.2 and one XP) installed. After the 5th forced reboot, I 'think' the issue is with multiple images doing multiple things at the same time. The most recent crash was during a shutdown of one image and log in on a second image. The VirtualBox Manager window goes away and a couple of seconds later, BOOM!

Posted by guest on August 27, 2012 at 04:35 PM BST #

I also ran in to trouble upon upgrading to Mountain Lion 10.8.1.

V Box 4.1.20 solved almost all my issues and is running XP stable.

The only thing I can not do is connect to the internet. This is odd since I can connect to my printers through the wireless MAC adapter in Guest XP.

Posted by Larry Amato on September 12, 2012 at 02:04 AM BST #

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