Created attachment 217295 [details] Ignore volumes labelled 'EFISYS'. The HAL policy rules already have an entry to ignore EFI volumes but they don't match the name FreeBSD uses. The attached patch adds the name FreeBSD uses so XFCE etc don't show the EFI volume.
Thanks for the patch, unfortunately, HAL has been removed from the ports tree in https://svnweb.freebsd.org/ports?view=revision&revision=564691. I'm closing this issue for now because of that.