Once again the problem of an ugly colour scheme returned. Instead of a sleek looking theme, I got the root theme which looks like it came out of Windows 10 years ago.

A Google search with the keywords “virtualbox ubuntu 11.04 ugly theme” led me to a Ubuntu forums thread with a link to the Virtualbox forums.

Here’s the solution which worked.

Open a terminal window, go to your home folder (don't forget that) and type:

sudo gedit .gtkrc-2.0 (DO NOT forget the dot in the beginning of the filename)
Type your password and when gedit opens copy/paste the following two entries in that new file.

include "/usr/share/themes/Ambiance/gtk-2.0/gtkrc"
gtk-icon-theme-name = "ubuntu-mono-dark"

The second line will fix the icons in Nautilus.
Save the file, close gedit and restart your VM and...