Error : Vagrant was unable to mount VirtualBox shared folders

[ashishnegi]

In latest master / v1.2 tag, i get error :

Vagrant was unable to mount VirtualBox shared folders. This is usually
because the filesystem "vboxsf" is not available. This filesystem is
made available via the VirtualBox Guest Additions and kernel module.
Please verify that these guest additions are properly installed in the
guest. This is not a bug in Vagrant and is usually caused by a faulty
Vagrant box. For context, the command attempted was:

mount -t vboxsf -o uid=10000,gid=10000 vagrant /vagrant
The error output from the command was:
: No such device

If i retry the command again, i see vagrant up stuck at

default: Running: inline script

Full log :

gitrepos\ops-class\vagrant>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Importing base box 'ops-class/ubuntu-16.04'...
==> default: Matching MAC address for NAT networking...
==> default: Checking if box 'ops-class/ubuntu-16.04' version '0.0.2' is up to date...
==> default: Setting the name of the VM: ops-class.org
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
==> default: Forwarding ports...
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: trinity
    default: SSH auth method: private key
==> default: Machine booted and ready!
[default] GuestAdditions versions on your host (6.0.4) and guest (5.1.10) do not match.
Reading package lists...
Building dependency tree...
Reading state information...
dkms is already the newest version (2.2.0.3-2ubuntu11.3).
The following NEW packages will be installed:
  linux-headers-4.4.0-51 linux-headers-4.4.0-51-generic
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 10.7 MB of archives.
After this operation, 77.8 MB of additional disk space will be used.
Get:1 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 linux-headers-4.4.0-51 all 4.4.0-51.72 [9,895 kB]
Get:2 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 linux-headers-4.4.0-51-generic amd64 4.4.0-51.72 [783 kB]
dpkg-preconfigure: unable to re-open stdin: No such file or directory
Fetched 10.7 MB in 39s (267 kB/s)
Selecting previously unselected package linux-headers-4.4.0-51.
(Reading database ... 38852 files and directories currently installed.)
Preparing to unpack .../linux-headers-4.4.0-51_4.4.0-51.72_all.deb ...
Unpacking linux-headers-4.4.0-51 (4.4.0-51.72) ...
Selecting previously unselected package linux-headers-4.4.0-51-generic.
Preparing to unpack .../linux-headers-4.4.0-51-generic_4.4.0-51.72_amd64.deb ...
Unpacking linux-headers-4.4.0-51-generic (4.4.0-51.72) ...
Setting up linux-headers-4.4.0-51 (4.4.0-51.72) ...
Setting up linux-headers-4.4.0-51-generic (4.4.0-51.72) ...
Examining /etc/kernel/header_postinst.d.
run-parts: executing /etc/kernel/header_postinst.d/dkms 4.4.0-51-generic /boot/vmlinuz-4.4.0-51-generic
Copy iso file C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the box /tmp/VBoxGuestAdditions.iso
Mounting Virtualbox Guest Additions ISO to: /mnt
mount: /dev/loop0 is write-protected, mounting read-only
Installing Virtualbox Guest Additions 6.0.4 - guest version is 5.1.10
Verifying archive integrity... All good.
Uncompressing VirtualBox 6.0.4 Guest Additions for Linux........
VirtualBox Guest Additions installer
Removing installed version 5.1.10 of VirtualBox Guest Additions...
Copying additional installer modules ...
Installing additional modules ...
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: Building the modules for kernel 4.4.0-51-generic.
update-initramfs: Generating /boot/initrd.img-4.4.0-51-generic
VirtualBox Guest Additions: Running kernel modules will not be replaced until
the system is restarted
VirtualBox Guest Additions: Starting.
VirtualBox Guest Additions: modprobe vboxsf failed
An error occurred during installation of VirtualBox Guest Additions 6.0.4. Some functionality may not work as intended.
In most cases it is OK that the "Window System drivers" installation failed.
Job for vboxadd-service.service failed because the control process exited with error code. See "systemctl status vboxadd-service.service" and "journalctl -xe" for details.
Unmounting Virtualbox Guest Additions ISO from: /mnt
==> default: Checking for guest additions in VM...
    default: The guest additions on this VM do not match the installed version of
    default: VirtualBox! In most cases this is fine, but in rare cases it can
    default: prevent things such as shared folders from working properly. If you see
    default: shared folder errors, please make sure the guest additions within the
    default: virtual machine match the version of VirtualBox you have installed on
    default: your host and reload your VM.
    default:
    default: Guest Additions Version: 5.1.10
    default: VirtualBox Version: 6.0
==> default: Mounting shared folders...
    default: /vagrant => C:/gitrepos/ops-class/vagrant
Vagrant was unable to mount VirtualBox shared folders. This is usually
because the filesystem "vboxsf" is not available. This filesystem is
made available via the VirtualBox Guest Additions and kernel module.
Please verify that these guest additions are properly installed in the
guest. This is not a bug in Vagrant and is usually caused by a faulty
Vagrant box. For context, the command attempted was:

mount -t vboxsf -o uid=10000,gid=10000 vagrant /vagrant

The error output from the command was:

: No such device

gitrepos\ops-class\vagrant>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'ops-class/ubuntu-16.04' version '0.0.2' is up to date...
==> default: Setting time zone to 'Etc/GMT-5'...
==> default: Running provisioner: shell...
    default: Running: inline script

[spaihippo]

vagrant plugin install vagrant-vbguest fixed it for me and I'm on Ubuntu 18.04. Hope that helps!

Edit: if you haven't watched it already, this video might also be helpful https://www.youtube.com/watch?v=taI5t05YKto