Re: VirtualBox?
I can't help you on virtualbox, except point to a youtube: https://www.youtube.com/watch?v=1t5kECk_U_Q
I'm running Remix on Linux Mint (following simple directions here: http://forum.xda-developers.com/remix/remix-os/remix-os-installation-rooting-t3293769).
My problem isn't getting it to run, but actually using it. It is familiar enough, but just enough different, that some actions seem exasperating.
Don't get me wrong! Remix is extraordinary in getting Android working in multiple, resizable windows. I was having trouble scrolling within the windows, getting app screen icons to open the app, having my gmail account suddenly being no longer associated with Remix after 20 minutes of operation.