I am following this question: How to install Ubuntu on VirtualBox? and I know want to remove the .iso, but it's not the same as in that question. Here is what I see:
What I should do?
I also tried from Machine -> Settings -> Storage, where I could locate the .iso file in the Storage Tree, but the right click on it, is giving me a list with one item, Remove attachment, but it's disabled.
unable to press ENTER to reboot. Powering off and back on should boot you into your installed system. This is being tracked in bug 1447038
– oldfred Jan 22 '16 at 23:08