The install screens are too large for the VBox initial window (i.e. before Guest Additions can be installed)
I got around this by using the screen reader option - then you can hear what options you are selecting when tabbing out of the visible window BTW it doesn't like dynamic vdi's either : best to use a fixed disk (which you can always expand later using the virtual media manager) - i've started with 30gb.
I had this same problem. Found a way around it. Goto into machine settings -> Display - Change Graphics Controller to - VBoxSVGA That fixed it for me. (Even if it says Invalid settings detected). Reboot VM.
same problem with VM-Fusion, installation process hanging on installation mode regarding display solution 800 x 600.
Initially this issue was reported with eOS beta, does this still happen to you with newest stable release?
Oh yes the problem still happens with Odin stable. There is a workaround for Virtualbox as @Rempala mentioned: fully shutdown your VM Go to Settings and change to VBoxSVGA Boot your VM As soon as the view is broken because 800x600, go to View > Virtual Monitor 1 > 1920x1080. It is not greyed out anymore.