The error when starting the vm can be seen in this video. I also scrolled through all the settings.
This is on Linux Mint 17.1 64 bit but I have had this same situation on may other distros. In the past it eventually worked but I have no idea why/how. I made no changes but eventually it just worked.
I've seen this happen multiple times.
Click on the VM to gain focus and press Alt-F2 (should dump you to a terminal) and then Alt-F7. The graphics session needs to be reset (at least that's my understanding). Quite a common problem with Linux VMs.
Off topic, but that video seems to be showing YouTube's new player. First time I have seen it in the wild. Not a big deal just mildly interesting.
Could not get that to work. Tried at different times during startup and after the error occurs. Still nothing.
Sorry, wrong key combination. I have the host key bound to Left Alt on my machine. The default is Right Control I think. Link explaining it here:
Loaded a kubuntu image and it gave the same error then worked. Maybe it auto resets? Gonna try a Ubuntu image again with those other key combos.
I've had that happen too. It doesn't work 2-3 times and then works on the 4th or something like that. Its odd. Try the key combos. It should be whatever your host is set to.
Using the host key plus f2/f7 worked just fine. My host key was the default (right ctrl) like you mentioned. Thanks for your help!