I have Lubuntu running as a virtual machine via VirtualBox.
Like many Ubuntu fans, I upgraded to version 16.04 LTS (Xenial Xerus) yesterday.
The reason for my upgrade was that Ubuntu 15.10 (a.k.a. Wily Werewolf) was not a Long-term Supported distribution.
Support for Ubuntu 15.10 ends in July 2016 while Ubuntu 16.04 LTS will be supported until April 2021.
The upgrade from Ubuntu 15.10 to Ubuntu 16.04 LTS went smoothly.
Following the upgrade, I rebooted my virtual machine.
And then came the familiar problem all of us confront with VirtualBox – screen resolution issue.
The problem is that the monitor settings (screen resolution) will be off and the desktop will not occupy the full screen.
Irritating but not a showstopper.
However, the problem can be fixed quickly.
This is how I fixed the screen resolution issue after upgrading from Ubuntu 15.10 to Ubuntu 16.04 LTS.
I opened up the terminal and installed virtualbox-guest-dkms.
tommy@johnson:~$ sudo apt-get install virtualbox-guest-dkms
[sudo] password for tommy:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
libnotify-bin virtualbox-guest-utils virtualbox-guest-x11
The following NEW packages will be installed:
libnotify-bin virtualbox-guest-dkms virtualbox-guest-utils virtualbox-guest-x11
0 upgraded, 4 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,986 kB of archives.
After this operation, 13.1 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 libnotify-bin amd64 0.7.6-2svn1 [6,584 B]
Get:2 http://us.archive.ubuntu.com/ubuntu xenial/multiverse amd64 virtualbox-guest-utils amd64 5.0.18-dfsg-2build1 [387 kB]
Get:3 http://us.archive.ubuntu.com/ubuntu xenial/multiverse amd64 virtualbox-guest-dkms all 5.0.18-dfsg-2build1 [551 kB]
Get:4 http://us.archive.ubuntu.com/ubuntu xenial/multiverse amd64 virtualbox-guest-x11 amd64 5.0.18-dfsg-2build1 [1,041 kB]
Fetched 1,986 kB in 0s (2,399 kB/s)
Once the installation is complete, there’s one more step.
You need to reboot the newly upgraded virtual machine (Ubuntu 16.04 LTS).
$ sudo reboot
After rebooting,you should now have access to the full screen.
As simple as that.