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Minecraft 1.20.1 Fabric — Fix Exit Code 1 & Startup Crashes

1 minRoute
Routeprism launcher mc 1 20 1 fabric fix exit code 1 crashminecraft 1.20.1 fabric fix exit code 1 & startup crasheshow to set up minecraft 1.20.1 fabric prism launcher

Blueprint for resolving Java version mismatches, broken mixins, and missing dependencies on Minecraft 1.20.1 Fabric using Java 17 (64-bit) and 4096–6144 MiB RAM in Prism Launcher.

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Minecraft & Loader
Minecraft 1.20.1 Fabric
Workflow Task
Fix Exit Code 1 & Startup Crashes
Required Java
Java 17 (64-bit)
Recommended RAM
4096–6144 MiB
Loader Stack
Fabric Loader + Fabric API

Blueprint: Minecraft 1.20.1 Fabric × Fix Exit Code 1 & Startup Crashes

This route configures **Minecraft 1.20.1 Fabric** inside Prism Launcher for resolving Java version mismatches, broken mixins, and missing dependencies. Start by creating an instance with **Fabric Loader + Fabric API** in the Version tab and assigning **Java 17 (64-bit)** under Java Settings.

Set Maximum Memory (`-Xmx`) to **4096–6144 MiB** so chunk loading, mods, and shaders run without garbage-collection pauses.

Prism Launcher screenshot showing the mod installation user-interface
Mods install straight from Modrinth and CurseForge.

Step-by-step checklist on Windows

  1. Install or update Prism Launcher from /download and click **Add Instance**.
  2. Select the Minecraft version and install **Fabric Loader + Fabric API**, then verify **Java 17 (64-bit)** is selected in Settings → Java.
  3. Use **Edit Instance** → **Mods** → **Download mods** to pull verified jars from Modrinth and CurseForge.

Frequently asked questions

Which Java version do I need for Minecraft 1.20.1 Fabric?

Use **Java 17 (64-bit)** with **4096–6144 MiB** allocated under Edit Instance → Settings → Memory.

Can I export this instance to share with friends?

Yes. Right-click the instance and click **Export** to save a `.mrpack` or Prism ZIP archive.

Get Prism Launcher

Windows, macOS & Linux

Free and open source. Sign in with the Microsoft account that owns Minecraft, then create your first instance.

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Prism Launcher on Windows showing several modpacks and instances