Talk:VirtualBox
To make a VM available from different user accounts on one computer (not having it running at the same time), you need to set up a few things:
Locate the virtual hard drive of the shared machine in a directory where different users have appropriate permissions. Create virtual machines on the different accounts, using that same virtual hard drive.
How it can be done
Create a shared folder, in your personal home folder, for you and other user(s):
Make other users member of the group yourusername (the easiest way is to install gnome-system-tools and use the users and groups -section. Manage groups > choose_yourusername > properties > add_other_users (detailed instructions here to mange users, and here to create a shared folder)
Change the permissions of the folder; right-click on in nautilus. In the permissions tab, change the group permissions for group yourusername to read & write.
Change the permissions for the files in the folder similarly (the button down in the nautilus properties window).
Create a virtual machine in VirtualBox. Do not use the default directory for a disk, but browse to the shared folder and save the disk image there. If you have an existing VM, delete it, delete its folder in ~/VirtualBox VMs as well, but keep its disk image, and move it to the shared folder first, then create a new VM, using the existing image as a harddisk. (if you try to relink the disk image in your existing VM, VirtualBox will complain the UUID already exists). On the other user's account(s), create similar machines, but use the hard disk image in the shared directory: /home/yourusername/shared_folder/machine_name.vdi (depending on the diskimage you created)
CREDIT TO: Jacob Vlijm
prevent VirtualBox from changing the permissions on the .vbox File
I had the same requirements (VM shared between two users) and the same problem (.vbox file with rw permission only to the last user of the VM).
To workaround this issue I created a vbox file for each user in the same folder (lets call them, for instance, xp_user1.vbox and xp_user2.vbox).
This would be the procedure:
(user1) Create the VM. The VM, its snapshots and the .vbox file have to be stored in a directory that can be accessed by both users (File|Preferences, Machine|Configuration).
(user2) Create the .vbox copy:
cp xp_user1.vbox xp_user2.vbox
(user2) Create the shared VM
Select the Machine|Add... menu item, navigate to the xp_user2.vbox location, and select that file.
In File|Preferences, set the default machine path to the .vbox location
Considerations:
If a snapshot is taken, the .vbox copy has to be updated
I tried to store the .vbox files at different directories but it did not work (location issues).