Create a shared folder in Virtualbox
You have a guest operating system in Virtualbox and you want to exchange some data between the host and the guest. For this purpose you want to use a shared folder. The shared folder should be writeable in the guest too.
In my case I had two Ubuntu systems as host and guest.
- create a shared folder on the host (e.g.
- create a shared folder on the guest (it can have the same path, e.g.
- install guest additions under the guest (Devices -> Install Guest Additions…), then restart the guest
- under the guest, go to Devices -> Shared Folders… Under Shared Folders, add the path of your shared folder (here
/opt/shared.folder.vbox). You can tick Auto-mount and Make Permanent if you want. Note that in my case, although I selected these two options, the shared folder was not mounted automatically.
Make the shared folder writeable
On the guest, you can manually mount the shared folder with the following command:
sudo mount -t vboxsf shared.folder.vbox /opt/shared.folder.vbox
As I figured out, only root can mount a shared folder.
However, it mounts the folder in read-only mode! To make it writeable, I had to add the following line(s) to
/etc/fstab under the guest:
# shared folder shared.folder.vbox /opt/shared.folder.vbox vboxsf defaults,rw,auto,uid=1000,gid=1000 0 0
I use the system as a normal user called jabba, and 1000 is its user id and group id. It can be found in
/etc/passwd (columns 3 and 4):
$ cat /etc/passwd | grep jabba jabba:x:1000:1000:Jabba Laci,,,:/home/jabba:/bin/bash
After a reboot, this folder is still not auto-mounted :( You can mount it with:
sudo mount /opt/shared.folder.vbox
But now it should be writeable…
Auto-mount shared folder at each boot
Now let’s put the dot on the “i” :) If you want your shared folder auto-mounted at each boot, add this line to
/etc/rc.local on the guest:
Make sure that it comes before the line “
On Ubuntu 16.04 I got this error: “/sbin/mount.vboxsf: mounting failed with the error: No such device”, though I had the Guest Additions installed. I found the solution here. Create the file
/etc/modules-load.d/virtualbox.conf and add these lines in it:
vboxguest vboxsf vboxvideo
vboxsf would be enough alone. These modules will be loaded with each boot.