The original Final Fantasy launched with a game-breaking bug that Square noticed too late to fix, so devs had to slip a warning into 500,000 copies of the JRPG: "Do not delete this..."

A whopping 38 years have passed since the original Final Fantasy released in Japan in 1987, and we're still learning more about the JRPG to this date – including the fact that it initially contained a game-breaking bug developers didn't notice until after its launch.

Final Fantasy composer Nobuo Uematsu reveals as much in a recent stream on Twitch (as translated by Genki in an online post). According to Uematsu, the first batch of Final Fantasy copies to release contained a destructive bug that Square devs weren't aware of until after the game was completed. To try and counter this problem for potential players, all of the studio's employees worked to slip pieces of paper with warnings into Final Fantasy boxes.

Final Fantasy Composer Nobuo Uematsu says there was a game breaking bug in the original release of Final Fantasy 1 so all the Square employees had to work to slip a warning paper into 500,000 copies of the game!They had already produced the cartridges when they found the bug so… pic.twitter.com/a8UWRL5xRpAugust 18, 2025

This resulted in over 500,000 copies of the first Final Fantasy entry housing the cautionary slip, which warned readers that, "if this happens, the game will break, so do not delete this..." As the warnings came after the JRPG's cartridges were produced, devs had to scramble to hand-write and manually insert each one – including Uematsu himself, pixel artist Kazuko Shibuya, programmer Ken Narita, and all other Square staff.

It sounds as though the bug was possibly related to item deletion or something of the sort, considering the warning Square placed inside the game's packaging. Thankfully, however, it also seems like not too many copies were affected in the grand scheme of things – after all, while 500,000 does appear to be a lot, it's nothing when compared to the millions that have likely sold since its fateful 1987 release date.

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After spending years with her head in various fantastical realms' clouds, Anna studied English Literature and then Medieval History at the University of Edinburgh, going on to specialize in narrative design and video game journalism as a writer. She has written for various publications since her postgraduate studies, including Dexerto, Fanbyte, GameSpot, IGN, PCGamesN, and more. When she's not frantically trying to form words into coherent sentences, she's probably daydreaming about becoming a fairy druid and befriending every animal or she's spending a thousand (more) hours traversing the Underdark in Baldur's Gate 3. If you spot her away from her PC, you'll always find Anna with a fantasy book, a handheld video game console of some sort, and a Tamagotchi or two on hand.