If you downloaded a file that isn't a standard .iso, xemu likely won't read it. You need to convert it to a standard ISO first.
xemu-img convert -i game.xiso -o game.cci -c
(Download xemu-img from the official Xemu website.)
This is optional but highly recommended for archiving your library. xemu convert iso to xiso
(Repository/flags may differ by implementation; refer to installed xiso --help.)
If you prefer a graphical interface, XDVDMulleter (beta 10 or later) is a classic Xbox tool. It’s outdated but still works. If you downloaded a file that isn't a standard
Important: Always ensure the option "Cross-File System" or similar optimization settings are checked if available in your tool, but generally, a straight creation works best for emulation.
This means your original ISO is truly corrupted or is a PC-only disc image. Try obtaining a different rip of the game – one that is “Redump” or “Xbox scene” compliant. (Download xemu-img from the official Xemu website
If you want, I can: