Leo's post was helpful, but not in the way expected. Had run the appropriate package installs and commands he listed dozens of times on fresh Ubuntu installs/VMs, with no luck.

Turns out the issue seems to be only certain versions of VBox are compatible with related versions of Ubuntu! Leo's version pair (VBox 5.1.30 and Ubuntu 16.04 LTS) ended up working, after trying 5+ other version pairs.

Here's the steps that worked:

Download exact VBox 5.1.30 and Ubuntu 16.04 LTS versions, and create a fresh VM with max video memory allowed Install Ubuntu from ISO onto the VM and do not install Ubuntu updates while waiting or third party software for media when prompted Do NOT run sudo apt update or sudo apt upgrade as mentioned in other blog posts Reboot and run: sudo apt install dkms build-essential module-assistant sudo m-a prepare Insert the Guest Additions CD using the VBox host menu. Run it. Reboot, and it worked.

On a side note, it would appear upgrading your VBox version can break your installation of Ubuntu! However I suspect you should be able to upgrade your Ubuntu indefinitely without a problem once you have 3D acceleration working using the Guest Additions, without any issue. Have not tested that theory yet though.

It may also be helpful for some to know that when 3D acceleration is not working in Ubuntu + VBox it will cause keys to stick repeatedly when typing, making it all but impossible to use Ubuntu. You can reproduce this by installing the latest (v17) Ubuntu with latest VBox (5.2) on Macbook Pro Retina / High Sierra. Install runs fine but after reboot cannot even login to Ubuntu as keys stick. For example, "test" will turn into tttttttttteeeeeeesssssssssstttttt" and then even a single backspace usually wipes the entire input field.