Prevent Crappy Launcher

A LaunchWrapper/ModLauncher CoreMod to prevent players from launching the game via a crappy launcher.

42.4K Downloads

forgeneoforgeutility

Rent Server with this Mod

About this Mod

A LaunchWrapper/ModLauncher CoreMod to prevent players from launching the game via a crappy launcher.

"Crappy Launcher" refers to a launcher that may cause performance and even compatibility problems that are extremely difficult to diagnose through debugging and other means, such as by messing with the game files and quietly adding JVM parameters for so called "optimization reasons".

Such a crappy launcher may also be a potential computer virus hazard, for example, calls system-level high risk libraries such as kernel32 for suspicious activities.

This mod plans to detect the crappy launchers exclusive to each OS by various methods, and throw exceptions when players try to launch the game using them.

To a certain extent, it could take care the confusion for modpack authors who need to solve potential problems that may be caused by launchers.

Only support Forge, no plans of Fabric port.

Use retro version for <= 1.12.2, modern version for >= 1.13.

Licensed under Mozilla Public License 2.0.

Available Versions

2.1-retrorelease

MC 1.6.4, 1.7.2, 1.7.3, 1.7.4, 1.7.5, 1.7.6, 1.7.7, 1.7.8, 1.7.9, 1.7.10, 1.8, 1.8.1, 1.8.2, 1.8.3, 1.8.4, 1.8.5, 1.8.6, 1.8.7, 1.8.8, 1.8.9, 1.9, 1.9.1, 1.9.2, 1.9.3, 1.9.4, 1.10, 1.10.1, 1.10.2, 1.11, 1.11.1, 1.11.2, 1.12, 1.12.1, 1.12.2forge

June 29, 2025

2.0-retrorelease

MC 1.6.4, 1.7, 1.7.1, 1.7.2, 1.7.3, 1.7.4, 1.7.5, 1.7.6, 1.7.7, 1.7.8, 1.7.9, 1.7.10, 1.8, 1.8.1, 1.8.2, 1.8.3, 1.8.4, 1.8.5, 1.8.6, 1.8.7, 1.8.8, 1.8.9, 1.9, 1.9.1, 1.9.2, 1.9.3, 1.9.4, 1.10, 1.10.1, 1.10.2, 1.11, 1.11.1, 1.11.2, 1.12, 1.12.1, 1.12.2forge

September 2, 2022

2.0-modernrelease

MC 1.13, 1.13.1, 1.13.2, 1.14, 1.14.1, 1.14.2, 1.14.3, 1.14.4, 1.15, 1.15.1, 1.15.2, 1.16, 1.16.1, 1.16.2, 1.16.3, 1.16.4, 1.16.5, 1.17, 1.17.1, 1.18, 1.18.1, 1.18.2, 1.19, 1.19.1, 1.19.2, 1.19.3, 1.19.4, 1.20, 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.5, 1.20.6, 1.21, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6forge, neoforge

September 2, 2022

How to Install Prevent Crappy Launcher on Your Server

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

Set forge Loader

In the panel under "Egg", select the forge loader and matching Minecraft version (1.21.6).

Install Mod

Open the mod browser in the dashboard and search for "Prevent Crappy Launcher". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

forgeneoforge

Minecraft Versions

1.21.6, 1.21.5, 1.21.4 (+74 more)

Server-side

✗ Unsupported

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Prevent Crappy Launcher server crashes on startup – what to do?

Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.6). You can switch loaders with one click in the panel.

Is Prevent Crappy Launcher compatible with forge and neoforge?

Prevent Crappy Launcher officially supports forge, neoforge for Minecraft 1.21.6, 1.21.5, 1.21.4. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Prevent Crappy Launcher – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Prevent Crappy Launcher consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.