How to install the VirtualBox Guest Additions:
1. Get the VBoxGuestAddiitons.iso file from http://www.virtualbox.org/manual/ch04.html
2. Make the VBoxGuestAddiitons.iso available to your “guest” OS: In the Devices menu open “CD/DVD Devices” and select checkbox next to the VBoxGuestAddiitons.iso or if the iso is not there use the Add button to locate and add the iso file to your list of available images. The effect of this will be that your guest OS will now see the VBoxGuestAddiitons CD image just as if it were a normal CD inserted into the machine’s CD/DVD drive.
3. On the Guest Additions CD run the proper install file for your operating system. This should install the Guest Additions to your system.
…if the above results in errors..
After running the installer you may encounter errors, e.g:
Verifying archive integrity... All good.
Uncompressing VirtualBox 3.2.12 Guest Additions for Linux........
VirtualBox Guest Additions installer
Removing installed version 3.2.12 of VirtualBox Guest Additions...
Uninstalling old VirtualBox DKMS kernel modules [ OK ]
Building the VirtualBox Guest Additions kernel modules [FAILED]
Your system does not seem to be set up to build kernel modules.
Look at /var/log/vboxadd-install.log to find out what went wrong. Once you have corrected it, you can run
/etc/init.d/vboxadd setup
to build them.
Doing non-kernel setup of the Guest Additions [ OK ]
Installing the Window System drivers
Installing X.Org Server 1.9 modules [ OK ]
Setting up the Window System to use the Guest Additions [ OK ]
You may need to restart the hal service and the Window System (or just restart the guest system) to enable the Guest Additions.
This means you are missing some of the VBox Guest Additions dependencies. These may be:
kernel-headers
kernel-devel
dkms
gcc
Use your package manager (e.g. sudo yum install gcc) to correct the situation and run the VB GA installer again. Once the above are installed the VBox Guest Additions installation should proceed without errors. Restart the installer procedure again:
# cd /media/VBOXADDITIONS
# ./VBoxLinuxAdditions-x86.run
You may get the feeling that it’s hung up at this step:
Building the VirtualBox Guest Additions kernel modules
but just give it a few minutes and it will complete (it’s just a lengthy procedure). Your screen should like like the example above, without any [FAILED] error messages (all should be [OK] now).
Why do I need Guest Additions?
Along with features like seamless mouse integration (the guest OS will detect mouse clicks inside its area) and shared Clipboard, one of the most useful features that the Guest Additions provide is Shared Folders.
The Shared Folder is a folder located on your real machine, which is also visible in your guest machine/OS and thus can be used to share files between the two. You can read more about this feature here.
This page has a more complete list of dependencies which you need in order to install Guest Additions: forum.virtualbox.org