Ubuntu – Ubuntu 18.10 (Guest VirtualBox) – black screen after install Guest Additions and reboot

Can you update to the new version 4.1.14?

To do this, add a new source:

sudo gedit /etc/apt/sources.list.d/virtualbox.list

And copy the following line into gedit, and save

deb http://download.virtualbox.org/virtualbox/debian precise contrib

Then add the signed key:

wget -q http://download.virtualbox.org/virtualbox/debian/oracle_vbox.asc -O- | sudo apt-key add -

And then do a sudo apt-get update && sudo apt-get dist-upgrade

I think this will solve your problem, because we use the latest version, and we have no problems.

Run

xrandr

You get similar to

Screen 0: minimum 320 x 200, current 800 x 600, maximum 1280 x 1280

VGA connected 800x600+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
       1280x1024      60.0 +   75.0  
       1280x960       59.9  
       1152x864       75.0     74.8  
       1024x768       75.1     70.1     60.0  
       832x624        74.6  
       800x600        72.2*    75.0     60.3     56.2  
       640x480        75.0     72.8     66.7     60.0  
       720x400        70.1

    * item is current.

It is list of resolutions you can set. Now you can change by using

xrandr -s Index

index is number starting from 0 as the first line.

OR

xrandr -s widthxheight