DISC I/O ERROR
Often happens right before a loading screen.
This error can appear when:
- The CD drive gives up reading because of a mechanical or optical issue.
- The game uses copy protection
- When a file requested for loading isn't found in the CD's table of contents (should never happen on an original CD, except if the TOC zone is physically damaged).
If the CD is an original one:
- It may be dirty or scratched
- The CD drive may need repair
If the CD is a copy:
- It may have been re-authored (not an exact copy of an original). Even if the files are the same, the CD image structure may be altered.
- It may use copy protection
This is the case for games using file versions in their ISO 9660 structure, like Metal Slug 2 - Super Vehicle-001/II. Most Windows ISO image editors strip the version info which is needed by the game to identify the files. Use mkisofs WITHOUT THE -N FLAG, or edit the loading tables in the main PRG file.