The Legend of Zelda: Ocarina of Time
Remnants of Ura Zeldas 64DD origins still remain in Ocarina of Time. Several error messages exist in the game's data regarding wrong disks being inserted. A "Disk" tag can also be made to appear in the title screen by modifying the RAM addresses of the game. A save file can also be flagged as a "Disk" save and a "Disk" icon will appear next to the save file on the file select screen. The file will be permanently grayed out and inaccessible, unless the game is tricked into thinking the expansion disk is inserted. Attempting to open the file afterwards will crash the game, presumably due to the game trying to load non-existent files.