Guides / How to install a Minecraft mod

How to install a Minecraft mod

5 min read

Installing a Minecraft mod comes down to one rule: the mod, the loader, and the Minecraft version all have to match. A mod built for Fabric on 1.21 will not run on Forge, and it will not run on 1.20 either. Get those three lined up and the mod just works. Get one wrong and the game crashes on launch or the mod never shows up.

This guide covers the manual route, where you install a loader and drop the jar in the mods folder yourself, and the easy route, where an Orca server picks the loader and version for you and the free desktop client launches the game. Pick whichever fits how much setup you want to do.

First, check which loader and version your mod needs

Every mod is built for one loader and a specific Minecraft version. Before you download anything, read the mod page and note both. The three loaders you will see:

  • Fabric, lightweight and quick to update to new versions. Fabric mods often also need Fabric API installed alongside them.
  • Forge, the oldest ecosystem with the deepest catalogue of content mods and modpacks.
  • NeoForge, a modern fork of Forge that most new Forge-style mods target on recent versions.
  • Match the Minecraft version too. A 1.21 mod needs the 1.21 build of its loader, not 1.20 and not 1.21.1.

Install the matching loader, then add the jar

Install the loader that matches your mod, then put the mod file where the game looks for it. For Fabric, run the Fabric Loader installer, and if the mod needs it, download Fabric API and treat it like any other mod. For Forge or NeoForge, run their installer, which bundles the loader for you. Either way the installer adds a new profile to the Minecraft launcher.

Once the loader is in, find your mods folder. On Windows it is at %appdata%\.minecraft\mods, and on macOS it is in the Library Application Support folder. Drop the .jar straight into that folder. Then open the Minecraft launcher, pick the loader profile you just installed, and hit play. Open the mods list on the title screen to confirm it loaded.

The no-setup way: play it on an Orca server

If you would rather skip the loader, the version matching, and the mods folder entirely, you can play the mod on an Orca server instead. The free desktop client fetches the mod, picks the loader and Minecraft version that match it, and launches the game for you. There is no installer to run and no jar to move by hand.

This is also how you test a mod you just built. Make a mod, load it on your free 1 GB server, and the desktop client for Windows, macOS, and Linux gets you in game in a couple of minutes. New to building mods? Start with how to make a Minecraft mod.

Common problems and how to fix them

Most failed installs come down to a mismatch. The usual suspects:

  • Wrong version. The mod and the loader profile must both be the same Minecraft version, down to the point release.
  • Missing Fabric API. Many Fabric mods crash on launch without it, so install it alongside the mod.
  • Mixing loaders. A Fabric mod will not load on Forge, and the reverse is also true. Pick one loader per profile. Unsure which? Read Fabric vs Forge.
  • Mod in the wrong folder. The .jar goes in the mods folder, not the resourcepacks or saves folder.

FAQ

Where is the Minecraft mods folder?

On Windows it is at %appdata%\.minecraft\mods. On macOS it is in Library Application Support minecraft mods. The folder appears after you install a mod loader. Drop the .jar straight into it.

Do I need Fabric API to install a Fabric mod?

Often yes. Many Fabric mods depend on Fabric API and crash on launch without it. Download it and put it in the mods folder alongside the mod. Forge and NeoForge bundle what they need.

Can I install a mod without a mod loader?

No. A loader like Fabric, Forge, or NeoForge is what loads the mod into the game. The one exception is skipping install entirely and playing the mod on an Orca server, where the desktop client sets up the loader for you.

Why does my game crash when I add a mod?

Almost always a mismatch: the mod and loader are different Minecraft versions, Fabric API is missing, or a Fabric mod was dropped into a Forge profile. Match the loader and version and install Fabric API if the mod needs it.

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