[17:12] <tomreyn> thanks!
[17:25] <tomreyn> There is another issue, or two, if you want. https://xubuntu.org/requirements/ says you need "about 8 GB of free space on your hard disk". The installer says you need exactly 8.6 GB minimum.
[17:25] <tomreyn> And if you have a disk with 8 GB, it tells you this: https://i.imgur.com/A6UcmlT.png
[17:26] <tomreyn> * 8.0 GB
[17:51] <tomreyn> with an 8.6 GB HDD, both the capacity check and the actual defaul (incl. downloading updates during installation) installation succeeds on this UEFI Virtualbox VM, and so does booting this system: 656 MB available on / after installation, 611 MB after installing updates, 752 after apt purge + autoremove. So 8.6 disk capacity would be  good to state everywhere (rather than 8 GB).