Sharing folders between Windows (host) and Ubuntu (guest) in VirtualBox

I have Windows 8 installed with Ubuntu 12.04 in Oracle VM VirtualBox and quite a few times I want to share files between them. For that, first you need to install VirtualBox Guest Additions for Linux. Guest additions consist of device drivers and system applications that optimize the guest operating system for better performance and usability.

To install Guest Additions go to Ubuntu Launcher and you would see VBOXADDITIONS_X.X.X_XXXX mounted.

Open it and click on "Open Autorun Prompt" button.

Click on "Run".

This will install the Guest Additions on Ubuntu. Shut down Ubuntu and go to VirtualBox. Select Ubuntu and click on "Machine > Settings". In the "Shared Folders" tab add a new folder.

Create a folder which would end up showing in "Machine Folder" section.

Start Ubuntu and now when you go to File System inside the folder media you would be able to see your shared folder with name sf_<SHARED_FOLDER_NAME>. But when I tried to paste text inside this folder I got an error with message -

The folder contents could not be displayed. You do not have the permissions necessary to view the contents of "sf_<SHARED_FOLDER_NAME>"

A little bit of research and I found this discussion which states that you need to be a member of the vboxsf group in order to access shared folder for VirtualBox. So just run the below command in your Terminal:

sudo gpasswd --add <USERNAME> vboxsf

And you are done!