mount gives unknown filesystem type 'vboxsf'
Try installing Virtualbox Guest Additions, it should take care of it.
- Start the Guest OS (UBUNTU)
- Click Devices in the top menu-bar (of the VBOX window housing Ubuntu)
- Click Install Guest Additions
That should prompt the download of Guest Additions and may open up the nautilus Window when the download is finished.
At that point, if it does not install automagically - you may need to open a terminal and navigate to that folder and execute the bash with
sudo ./whateverTheArchitectureTypeYouHaveIs.sh
It offered to do it automatically for me.
(note, it does require super user permissions in the guest os.)
Edit
Here is a windows screenshot (Version 4.2.4r81684 - however, I have seen the option since I can remember with VBox. Looks like others do not have menus either around the web, I'd like to disable mine for sure.), looks basically the same. You should be able to hit the Host+D keys to install them (sorry for overlooking that before). Host, by default, is Right Control.
Maybe it's simpler to install the guest additions using
sudo apt-get install virtualbox-guest-x11
and then reboot.
So as per nerdwaller's post, I did need to install Virtualbox Guest Additions to get the vboxsf type in there... I still don't know why this is needed with Ubuntu and not OpenSUSE, but that doesn't really matter too much I guess.
None of the previous suggestions actually worked to get the guest additions installed. What I ended up doing is pretty simple:
On the Oracle VM VirtualBox Manager, when you click the Ubuntu virtual machine, you can select "Settings". This opens the following window:
As seen here, I clicked on Storage then the main IDE Controller (it was set to nothing) and I updated the CD/DVD Drive to point to:
C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso
Where the guest additions .iso was stored by default.