Mount shared folder to Ubuntu in VirtualBox

We cannot use the /media/sf_Dropbox as a mount point because of permission. Create new folder as <~/Dropbox> and mount shared folder for VirtualBox by

>>sudo mount -t vboxsf <Dropbox> <~/Dropbox>

The mount above performs by root so normal user cannot write on the folder. We can define user and group of normal user by specify uid and gid as shown below

>>sudo mount -t vboxsf -o rw,uid=1000,gid=1000  <Dropbox> <~/Dropbox>

And you can unmount by

>>sudo umount -a -t vboxsf