Litematica MaLiLib Missing: Crash on Launch

Litematica 1.21.4 refuses to launch when MaLiLib is missing or older than 0.23.5. Fabric stops on that dependency before a world exists, so the M menu cannot open.

Generate a .litematic

Why “just add the Litematica jar” crashes

The 1.21.4 fabric.mod.json depends on minecraft 1.21.4 and malilib >=0.23.5-. There is no copy of the library inside the Litematica jar. Fabric treats a missing or too-old dependency as an incompatible mod set and shows that on the load error, with the detail in logs/latest.log. Guessing a keybind cannot fix a mod that never finished loading.

MaLiLib 1.21.4 then depends on fabric-networking-api-v1 >=4.3.7 and fabric-resource-loader-v0. Those modules ship in Fabric API. Litematica itself does not list Fabric API. If the log names those API ids, the library is the one that is unsatisfied. Older README text that Fabric API is unnecessary describes Litematica’s own depends, not this MaLiLib file.

Steps

Read the Fabric error or logs/latest.log in the instance that crashed. Look for the mod ids litematica and malilib.
Match Minecraft 1.21.4. The Litematica fabric.mod.json for that branch depends on minecraft 1.21.4 and malilib >=0.23.5-.
Put MaLiLib and Litematica in that instance’s mods folder. Not resourcepacks, and not a different profile.
If the log names fabric-networking-api-v1 or fabric-resource-loader-v0, install Fabric API for 1.21.4 as well. Those are MaLiLib’s own depends.
Launch a world and press M. A crash screen means the menu cannot exist yet.

Download both mods for 1.21.4 from the same host, Modrinth or CurseForge, filtered to Fabric. A 1.20.1 or 1.21.1 jar in a 1.21.4 instance fails the minecraft dependency even when the file name looks right. Put them in the mods folder of the profile you launch. CurseForge and Modrinth App do not read the global .minecraft/mods folder. Install steps with the loader are on how to install Litematica.

What the log is distinguishing

malilib missing or not >=0.23.5-: Litematica’s depends failed.
litematica at or below 0.21.1 next to current MaLiLib: the library’s breaks entry.
fabric-networking-api-v1 or fabric-resource-loader-v0: MaLiLib’s depends, fixed by Fabric API for 1.21.4.
No Litematica line at all: the jar is in another instance, or the loader is not Fabric.

environment is client. The hologram is not a server mod. Dropping the jar into a dedicated server’s mods folder does not show ghost blocks to other players, and a server loader may reject the client-only file. Realms and servers you do not control are covered on Litematica on a server.

Do not rename the jar to force a version. Fabric reads the version inside the jar, not the file name. Do not put the jars in shaderpacks or resourcepacks. Fabric never reads those folders as mods, so the log will still say malilib is missing. Keep the two jars on the same Minecraft version line. A MaLiLib build for 1.21.5 in a 1.21.4 instance fails MaLiLib’s own minecraft dependency, which looks similar on the error screen and is not fixed by downloading Litematica again. The main menu key cannot be tested from the title screen. Fabric’s error appears before you reach a world, and the M handler only runs once the client is in game. Seeing the Mojang logo and then an incompatible-mods screen is still this dependency, not a schematic bug. Fabric does not care about jar order in the mods folder. It reads each fabric.mod.json. A file named malilib that is actually an older build still fails >=0.23.5-. Match the Minecraft version filter on the download page to 1.21.4 for both jars, and for Fabric API if the log asks for it. The trailing hyphen in the version range is part of the string in the file; the log quotes that range when the dependency check fails.

Limits

After a clean launch, an unbound M is a config problem, not a missing jar. Search openGuiMainMenu in the instance config/litematica.json. The default string is M. That recovery is the hotkey list. A file that will not appear in Load Schematics is a folder or extension problem, on how to import a litematic file, not another copy of MaLiLib.

This site’s schematics are data version 4189 (Java 1.21.4). Installing a matching mod on 1.20.1 so the game “stops crashing” loads a different block set than the file. Use a 1.21.4 Fabric instance for these holograms. The mod still does not give you the blocks; it only gets you to the menu.

FAQ

Does Litematica include MaLiLib?

No. They are separate jars. Litematica’s fabric.mod.json lists malilib under depends. The README tells you the library is required.

The game reaches the menu, but M does nothing.

Then the crash is already over. Either the Fabric jars never loaded in this instance, or openGuiMainMenu was cleared. Check the log for the mod ids, then the hotkey file.

Will a Forge or NeoForge pack load these jars?

No. The 1.21.4 files are Fabric mods, and Litematica’s environment is client. A Forge-only mods folder ignores them.

I have a newer MaLiLib and an old Litematica.

MaLiLib 1.21.4 lists a breaks entry for litematica versions at or below 0.21.1. Update Litematica to the build that matches that MaLiLib, instead of mixing years.

Questions: hello@minecraftschematicgenerator.com

Reviewed 2026-09-27. Not affiliated with Mojang or Microsoft.