This is a short guide on what to do first when a fresh Ubuntu installation crashes in Virtual Box:

• Make sure you had enabled VT-x/AMD-V in BIOS.


• Leave some CPU power for the host (if all cores were assigned, define an execution cap).


• Leave enough RAM for the host OS (how much depends on the OS and applications running).


• Install the guest additions.



• Update your guest Ubuntu for bugfixes:

  
  
  
  
  
  1. Boot Ubuntu to the login screen.
  
  
  2. Press HOST + F1 for a terminal.
     
     _{(alternatively to 1.- 2. we may also boot to a root shell with networking. Then no sudo is needed for commands below)}
  
  

  3. Type the following commands:

     
     
     

     sudo apt-get update
     
     sudo apt-get dist-upgrade
     
     

  
  

  4. Enter your password (nothing is displayed!).

  
  
  5. Answer Y to download and install updates & bugfixes.
  
  

  6. After done type reboot.

  
  

  7. In case dkms was not installed in the guest we will have to re-install the guest additions.