Minecraft Updated April 26, 2026

How to Install a Modpack (CurseForge, Modrinth, ATLauncher)

Get a CurseForge, Modrinth, or ATLauncher modpack running on your dedicated Minecraft server — including common issues with Java versions and RAM.

MinecraftmodpackCurseForgeModrinthATLauncherForgeFabricmods

Understanding Modpack Server Files

Modpacks come in two parts: the client-side pack your players install in their launcher, and the server pack you install on your dedicated server. They're different files — you need the server pack, not the client pack.

Most CurseForge and Modrinth modpacks offer a dedicated "Server Pack" download. ATLauncher has an "Export server pack" option.

Step 1: Download the Server Pack

CurseForge:

  1. Go to the modpack page on CurseForge.
  2. Click Files, then find the latest release.
  3. Look for a "Server Pack" file — it's often listed alongside the main download.

Modrinth:

  1. Find the modpack on Modrinth.
  2. Go to the Versions tab.
  3. Look for a server-side .mrpack or zip download. Some packs include server files; others link to a separate server pack.

ATLauncher:

  1. Right-click your installed pack instance.
  2. Choose Create Server or export the server files.

Step 2: Stop Your Server and Set the Correct Server Type

The server pack will tell you which loader and version it requires (e.g., "Forge 1.20.1 - 47.2.20" or "Fabric 1.21.4").

In the WISP panel:

  1. Stop your server.
  2. Go to the Startup tab.
  3. Set the Server Type to match (Forge, NeoForge, or Fabric) and set the Minecraft Version and Loader Version to match the modpack requirements exactly.

Step 3: Upload the Server Pack Files

  1. Extract the server pack zip locally.
  2. Upload all extracted files to your server root via SFTP or the WISP file manager. This typically includes:
    • mods/ folder
    • config/ folder
    • Any included scripts or start files (you can ignore platform-specific start scripts like startserver.bat — WISP manages startup)
    • server.properties (if included — review before overwriting your existing one)

Do not upload the Forge/NeoForge/Fabric installer jar — WISP handles downloading and installing the loader itself.

Step 4: Accept the EULA

Make sure eula.txt in your server root contains:

eula=true

Step 5: Start and Watch the Console

Start the server and monitor the console. The first start with many mods can take 3–10 minutes while mods are loaded. You'll see lines like:

[Forge] Loading mod: somemod
[Forge] Loaded 247 mods

Once fully started, you'll see the Done! line with a startup time.

Common Issues

Wrong Java version: Many Forge packs for 1.16–1.18 require Java 8 or 11, while 1.19+ packs require Java 17 or 21. Check the modpack requirements. You can set the Java version in the WISP Startup tab.

Not enough RAM: Modpacks are memory-hungry. A small pack needs at least 4 GB, large ones (100+ mods) need 8–12 GB. Increase your -Xmx allocation — see How to Adjust Your Minecraft Server's RAM Allocation.

Missing server-specific mods: A few mods are client-only and don't have a server jar. Remove any mod that crashes on startup with "client-only" in the error message.

Crash on startup: Check the crash-reports/ folder in your server root — Forge writes detailed crash logs there that usually pinpoint the offending mod.

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