Mount with Virtual Box 'automatic mounting': Some systems may need option comment=tomount in their fstab entry ( source). It may then help to append the vboxsf kernel module to /etc/modules. On some systems the vboxsf kernel module is not yet loaded at the time fstab is read on boot.

One possibility is to mount with defaults, or to give specific mount options (e.g. Replace name_of_share and /path/to/mountpoint with your individual setup (the directory for the mountpoint has to be created first). Then we may put the following line in our etc/fstab file: /path/to/mountpoint vboxsf 0 0

To mount a shared folder using the vboxsf filesystem provided with Guest Additions we first need to make sure prerequisites are met. It is up to personal preference which option works best in our setting. Finally add user to vboxsf group ( replace USER_NAME with what printed in last command.To always mount a Virtual Box 'shared folder' on booting an Ubuntu guest we have two options.When terminal opens, run command to check your username in case you don’t remember: whoami.Open a terminal window from system app launcher.Firstly, start the virtual machine and login.Here I’m going to do it via a single command: There are a few ways to add an user to a group. All you need to do is add your user into this group. The shared folder belongs to vboxsf group in the guest. You do not have permissions necessary to view the contents of “xxx” Or it prompts permission issue while accessing from the left pane in file manager: GDBus.Error.Failed: Unix process subject does not have uid set. And it pops up an error dialog when you trying to open it:

However, after you created one, the shared folder is marked with cross and lock icons. Shared Folders is an useful feature for file sync between Virtualbox host and guest OSes. Running Ubuntu as virtual machine via VirtualBox? You may encounter permission issue to access the shared folder between host and guest.

Ubuntu virtualbox shared folder