SUMMARY Wit the guest additions shipped with Neon, it's not possible to resize the VirtualBox guest after a default installation. The issue is that the default graphics adapter is VMSVGA, which is only supported in newer GuestAdditions (according to several forum topics e.g. [1] [2] ) STEPS TO REPRODUCE 1. Install Neon User Edition in VirtualBox with default settings (except larger HDD) 2. Try to resize the window after installation OBSERVED RESULT Impossible to resize (Note: It's possible to resize after switching the graphics adapter to VBoxSVGA, which is not recommended for Linux guests) EXPECTED RESULT Window should resize ADDITIONAL INFORMATION [1] https://forums.virtualbox.org/viewtopic.php?f=3&t=93668 [2] https://forums.virtualbox.org/viewtopic.php?f=3&t=94889
Will most likely be fixed after Neon is updated to 20.04: https://launchpad.net/ubuntu/focal/+package/virtualbox-guest-additions-iso Thanks kbroulik for pointing this out - closing, sorry for the Spam :-)