I have been able to successfully mount a shared folder between my VirtualBox Ubuntu instance (v17.10) and my Windows 7 Enterprise (host) using the following code in the Terminal:
$ mkdir ~/guest_shared $ sudo mount -t vboxsf shared ~/guest_shared
Here, my host folder I want to share is C:\shared and the mount source folder is ~/guest_shared. In the settings for VirtualBox, I have set the shared folder to C:\shared. This worked just fine after booting up my VM for the first time and after installing Guest Additions. I am able to share files between the VM and my host computer.
I'm now trying to change the host folder I want shared.
I create a different folder on my Host that I want to share, go back into the VirtualBox Settings >> Shared Folders for my VM, deleted the old shared folder host path (C:\shared) and changed to the new host shared folder path. This new path is C:\Users\123456\Desktop\Shared
I re-typed my previous code as such in Terminal to try to link my ~/guest_shared folder on my VM with the new folder on my host:
$ sudo mount -t vboxsf shared ~/guest_shared
However I am getting the error "/home/osboxes/guest_shared: can't find in /etc/fstab".
I either have bad syntax or I am missing a step.