Software used:
Host: Windows 7
VirtualBox: v4.3.6
Guest: MintMATE 16

1) Create a folder on your host machine, I like to have mine on the Desktop, but you can have it wherever you want. I recommend creating a file in the folder so that you can tell if the share is working.
2) Start VirtualBox and open the settings for your Mint system.
Add a “Machine Folder” and select the folder you want to share (the one you created in step 1).

You will need to give it a name. Check the “Make Permanent” box so you don’t have to repeat these steps.

You can then check “Auto-mount” if you want VirtualBox to automatically mount the share folder. If you do this it will be mounted in /media directory, along with the prefix “sf_”. The other option is to manually set up where we want it to mount.

4) Start your virtual OS.

Option 1:

If you checked “Auto-mount” in step 2) the share folder will actually be mounted in /mdeia. The problem is that your user isn’t a member of the vboxsf group (meanig you can’t open it). We can fix this by adding our-self to the group:
     sudo gpasswd -a vboxsf
     sudo reboot

You should now be able to navigate to the folder:
    cd /media/sf_/

Note: “In Linux guests, auto-mounted shared folders are mounted into the /media directory, along with the prefix “sf_”. For example, the shared folder myfiles would be mounted to /media/sf_myfiles.

This isn’t very convenient, so we can create a link to the mounted share:

    ln -s /media/sf_Share/ Desktop/

Alternate method from HTG:

sudo adduser [username] vboxsf

To verify you are in the vboxsf group, you can type “id [username]” (without the quotes, and replacing “[username]” with your username) at the prompt and press Enter. All the groups of which the specified user is a member display.”

Option 2:

If you want to set up the mount point yourself you will need to continue with these steps.

5) We now need to create a folder where the shared folder will be “mounted”. In terminal (CTRL + ALT + T):
    mkdir Desktop/VirtualBoxShare

6) You can now try mounting the share to this folder:
    sudo mount -t vboxsf Share Desktop/VirtualBoxShare/

7) If you go to the desktop and try and open this folder (or ls Desktop/VirtualBoxShare/), it will just hang… something is wrong. 

From my understanding Guest Additions has not been configured for the current user. To rectify this we need to reinstall it.

From the “devices” menu select “Insert Guest Additions CD image…”, this should automatically mount the CD on the desktop.

Then run the installer:
    sudo /media//VBOXADDITIONS_4.3.6_91406/
Reboot the system:
    sudo reboot

Now try remounting the share:
    sudo mount -t vboxsf Desktop/VirtualBoxShare/

If you open the mount point, it should work.

8) The next thing you probably want to do is mount the share automatically when you start Mint. 

I originally tried to edit the fstab file (similar to this previous post), which is what it says in the VirtualBox documentation, but this didn’t work:

     sudo gedit /etc/fstab (or use nano)

At the bottom of the file add a new line that reads:
    Share /home//Desktop/VirtualBoxShare vboxsf defaults 0 0
        where: [ vboxsf defaults 0 0]
Apparently fstab mounts the file system before vboxvfs has even been loaded. Luckily we can just put our mount command in the /etc/rc.local file:
    sudo gedit /etc/rc.local
Before the”exit 0″ command add the mount line from above (you don’t need sudo anymore as rc.local will be executed as a superuser. You do however need to specify the full directory):
    mount -t vboxsf Share /home/felix2/Desktop/VirtualBoxShare/
Save and reboot to try it out:
     sudo reboot
If everything worked, you should now have the shared folder mounting automatically!