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Monsters & Memories "Fatal Error" at launch: fix

Monsters & Memories server status →

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IsThisGameDown

Last checked

October 15, 2026

r/MonstersAndMemories: "Crash upon launching" ↗

A box that just says "Fatal Error" (no log, no other message) appears when you launch Monsters & Memories or right after you click Play.

Also appears as: monsters and memories fatal error, monsters & memories fatal error, Fatal Error, fatal error when clicking play, monsters and memories crash on launch, monsters and memories smart app control, monsters and memories blank error box

Most likely your PC, not Niche Worlds Cult's servers. In one Reddit thread (June 20, 2026) the poster found Windows Smart App Control was blocking the app as untrusted, and confirmed that sorting it out fixed the blank "Fatal Error" box. A commenter said it may explain other blank Fatal Error boxes. That is one confirmed case, not a pattern.

A second poster (September 25, 2026) got a "fatal error" popup right after clicking Play following an update. Someone suggested a full uninstall and reinstall; the poster said they would try it and never reported back, so that fix is untested.

No developer statement or Known Issues entry for this error was found.

Fix it, step by step

  1. Check Windows Security for a Smart App Control block

    Open Windows Security > Virus & threat protection > Protection history and look for a Smart App Control or "Blocked app" entry that names the Monsters & Memories launcher or client (Microsoft's own page says to look here when the block popup disappears too fast). Then open App & browser control > Smart App Control settings to see whether it is On. In the June 2026 Reddit thread, the poster's problem was Smart App Control blocking the app as untrusted.

  2. Stop Smart App Control blocking the game, then relaunch

    If Smart App Control is blocking it, the thread's poster confirmed that getting past the block fixed the error, but didn't say how. The option Microsoft documents is Windows Security > App & browser control > Smart App Control settings > Off, then start the game again. Know the trade-off first: Microsoft says you can't return to evaluation mode without resetting or reinstalling Windows, though recent Windows updates let you turn it back on without a clean install. Only one thread confirms this fix, so skip it if Protection history shows no block.

  3. Uninstall and reinstall the game (unconfirmed)

    For a "fatal error" popup right after clicking Play, a commenter suggested a full uninstall and reinstall. The poster said they would try it and never reported whether it worked.

  4. Note

    No confirmed fix yet if Smart App Control isn't blocking the game. Report it to Niche Worlds Cult on the official forum or Discord with your Windows version; this page will be updated.

    Unconfirmed

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Say where you are, what you see on screen, and whether any fix worked for you.

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What people are saying

Notes from players who've hit this one — no time limit, an answer from months ago is still an answer.

  • Nothing reported here yet.
← SERVER-DID-NOT-FINISH-CONNECTING

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