Virtualbox: How can I get a usable screen resolution inside the Guest OS

Question

I have just installed the virtualbox application on my Ubuntu 14.04 OS (host OS).
I then installed another Ubuntu 14.04 "inside" the VM i.e. the guest OS. The problem is the resolution is tiny and unusable and I need to increase the resolution "inside" the guest OS

here is what I have tried already

starting with a brand new install of Ubuntu 14.04 "inside" the VM

Install and configure the virtualbox guest additions

• sudo apt-get install virtualbox-guest-additions-iso - (run from inside the guest OS)
  this seemed to attempt to modify/build kernel modules, and there were some failures.
• Then set x86 virtualization settings (again inside the guest OS)
  1. Go to System settings → Software and Updates → Additional drivers
  2. Use x86 virtualization solutions...
  3. then reboot VirtualBox

Then what am I supposed to do - from there?

I have tried going into (from the host) virtualbox application -> file -> preferences -> display, then apply a "hint" of say 800x600.
But when I start the virtual box the res. is still something like 640 x 480 If I go into the guest OS'es display settings - there is still no option

I have also googled for a solution and see there are answers, but they are outdated, give various solutions that dont work for me

Answer 1

Before installing Guest Additions with the VBoxLinuxAdditions.run script, you must install the kernel headers package and a few other packages.

Run this command:

sudo apt-get install build-essential linux-headers-\`uname -r\` dkms

Then run the VBoxLinuxAdditions.run script.