Cleanroom relauncher unofficial
🟡 Updated this year⚠️ Install Order · 2 steps
Install in this order, then this mod last — most mods fail to load without their framework and dependencies in place.
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🔍 Analysis
- 👍 0.0% endorsement rate
- 🏆 #131 of 344 forge mods in this game by downloads
📋 About This Mod
# **THIS IS AN ALTERNATIVE, NOT A FORK!** ## This mod can: - Download and install Cleanroom automatically if you are running MMC-based launchers - Download and launch Cleanroom if you are using other launchers ## Difference compare to official one: - A config option to use local Cleanroom mmc pack, which allow the installation of action builds - Allow modpacks to ship default config Cleanroom version and args - Proxy config for mmc zip & libraries downloading - Maven mirror. Only useful for players in certain regions though - Custom library path, allow reusing libraries with existing launchers ## **Highlight Features for Pack Makers** - You can ship a custom default Cleanroom mmcpack with your pack, which won't be updated - You can ship a JRE with your pack (by filling relative path), so your players don't need to install new Java themselves - You can ship all libraries in your pack, which will means _instant one-clicked relaunch_ ## About Java 8u51 Official launcher ships with outdated Java 8u51 (released 2015), which doesn't contain certificates of later Let's Encrypt (used by Cleanroom maven) and Azure (used by libraries.minecraft.net). The mod will add those certs into JVM if old java detected. In fact, I added whole keystore from latest Java. But there's another bug in 8u51 that will cause deadlock in multi-thread downloading. Updating your JVM is always the best solution. ## About bundled libraries & files * Apache Httpcomponents 5: Shadowed to use multi-thread download. * java-utils: Created by CleanroomMC, used to detect installed JVMs. * MigLayout: Used to provide a decent GUI layout. * sslcontext-kickstart: Used to import keystore. * cacerts.jks: Keystore copied from latest Temurin JRE 8.0.462+8. * mmcpack.zip: Latest Cleanroom 0.3.30-alpha mmc zip. Can be verified by comparing checksum to (https://github.com/CleanroomMC/Cleanroom/releases/tag/0.3.30-alpha). ## If you want to… 1. __Update Cleanroom version__: remove mmcpack.zip and mmcpack/ folder in relauncher/, then launch the game. 2. __Rollback to Forge__: Disable the mod if you are using regular launcher, change game version, lwjgl version and Forge version back to regular in MMC instance setting if you are using that. ## Note By MMC-based launchers, I mean MultiMC, PolyMC and PrismLauncher. __You need to install a Java 21 to use this!__ __This is a client only mod! For server, please download installer jar from Cleanroom repository.__ **If anything gone wrong, remove cleanroom\_relauncher.cfg config file and try again!**
# THIS IS AN ALTERNATIVE, NOT A FORK!
## This mod can:
- Download and install Cleanroom automatically if you are running MMC-based launchers
- Download and launch Cleanroom if you are using other launchers
## Difference compare to official one:
- A config option to use local Cleanroom mmc pack, which allow the installation of action builds
- Allow modpacks to ship default config Cleanroom version and args
- Proxy config for mmc zip & libraries downloading
- Maven mirror. Only useful for players in certain regions though
- Custom library path, allow reusing libraries with existing launchers
## Highlight Features for Pack Makers
- You can ship a custom default Cleanroom mmcpack with your pack, which won't be updated
- You can ship a JRE with your pack (by filling relative path), so your players don't need to install new Java themselves
- You can ship all libraries in your pack, which will means _instant one-clicked relaunch_
## About Java 8u51
Official launcher ships with outdated Java 8u51 (released 2015), which doesn't contain certificates of later Let's Encrypt (used by Cleanroom maven) and Azure (used by libraries.minecraft.net).
The mod will add those certs into JVM if old java detected. In fact, I added whole keystore from latest Java.
But there's another bug in 8u51 that will cause deadlock in multi-thread downloading. Updating your JVM is always the best solution.
## About bundled libraries & files
Apache Httpcomponents 5: Shadowed to use multi-thread download. java-utils: Created by CleanroomMC, used to detect installed JVMs. MigLayout: Used to provide a decent GUI layout. sslcontext-kickstart: Used to import keystore. cacerts.jks: Keystore copied from latest Temurin JRE 8. 0. 462+8. mmcpack.zip: Latest Cleanroom 0. 3. 30-alpha mmc zip. Can be verified by comparing checksum to (https://github.com/CleanroomMC/Cleanroom/releases/tag/0. 3. 30-alpha).
## If you want to…
1. __Update Cleanroom version__: remove mmcpack.zip and mmcpack/ folder in relauncher/, then launch the game. 2. __Rollback to Forge__: Disable the mod if you are using regular launcher, change game version, lwjgl version and Forge version back to regular in MMC instance setting if you are using that.
By MMC-based launchers, I mean MultiMC, PolyMC and PrismLauncher.
__You need to install a Java 21 to use this!__
__This is a client only mod! For server, please download installer jar from Cleanroom repository.__
If anything gone wrong, remove cleanroom\_relauncher.cfg config file and try again!
📊 Mod Details
- Game
- Minecraft Mods
- Author
- kappa-maintainer
- Version
- 0.8.3-beta
- Downloads
- 8,031
- Endorsements
- 2
- Category
- forge
- Created
- 6/8/2025
- Updated
- 8/4/2026
- Game Versions
- 1.12.2
🔧 How to Install Minecraft Mods Mods
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❓ Frequently Asked Questions
Which Minecraft Mods versions does Cleanroom relauncher unofficial support?
The author lists 1.12.2. Other versions may work but are untested by the author.
What is the latest version of Cleanroom relauncher unofficial?
Version 0.8.3-beta, published 2026-08-04 with 8,031 downloads recorded at the source.
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