virtualbox.org

The iso file for the guest additions is located under the Virtualbox.app directory.

When you want to mount it as a cdrom in the configuration of the virtual machine, you can't open the directory.app.

So you have to first use the finder, in the application directory, you go to the virtualbox.qpp file, right click on it to show the content of the package, and under Contents/MacOs, you will find the iso file for VBoxGuestAdditions.iso.
Copy it to the desktop and mount it now.

Hope this helps.

Would it not be easier to simply click on the devices tab (top left title bar on running guest) and select install guest additions?

These are Mac users remember, so by definition they like to make life difficult for themselves...

^its not to make their life difficult.. its each others convnience.... its just a difference of opinion, who knows, they might have tough time with windows..??

nchodz wrote:^its not to make their life difficult.. its each others convnience.... its just a difference of opinion, who knows, they might have tough time with windows..??

"It's", "It's","convenience","Windows" At least some of us can spell.