I prefer to use Boxes, but it’s missing an absolutely essential feature that makes it almost impossible to use. When you first create a virtual machine with a new ISO image, you can select EFI boot, but if I create a new virtual machine with the same ISO then you can’t and it defaults to legacy BIOS, which means it will never boot and installation always fails. It literally doesn’t even give you the option to enable EFI if you’ve already created a virtual machine with that same ISO file. And then you can only change Preferences after the virtual machine has been created. Boxes really needs to have much better setup features where you can customize the virtual machine before it’s booted and installed to virtual disk. Thanks so much.
I should add that this doesn’t happen for mainline distributions like Fedora and Ubuntu, but it does with lesser-known distributions such as Void and others.
This looks like a bug in Boxes. Please file it in the bug tracker here: Issues · GNOME / GNOME Boxes · GitLab (after checking that it hasn’t been reported yet).
Please include the exact steps one can follow to reproduce the problem.