Improved Cleanroom Relauncher
by Bruv Network
Improved Cleanroom Relauncher automates the first-run setup for Forge 1.12.2 instances that launch the Cleanroom Loader.
What it does
On first launch the relauncher picks the latest Cleanroom Loader release, fetches the Java version it needs for the operating system and processor architecture, and writes the Java path into the instance configuration. Setting up the required libraries happens only once, and a progress popup reports the status while archives are fetched and extracted.
Transfers resume and retry automatically after a failed attempt. The major Java version and the Java distribution can each be set as configuration defaults, and a change to javaVersion in the config is applied on the next start. Java runtimes are cached under the user home folder in .cleanroom/relauncher/java, sorted by distribution, version, OS and architecture, so each combination is fetched once.
The package is aimed at modpacks, where the same setup has to work on different machines. It detects x64 and ARM64 systems, including Intel x64 and Apple Silicon (aarch64) Macs. If automatic configuration fails, a GUI lets the user set the Java path and other options by hand.
Key features
Automatic Java setup
Fetches the Java runtime that matches the OS and architecture, then writes its path into the config.
Setup progress popup
A dialog shows transfer progress and extraction, so the first launch can be followed without a console.
Resumable transfers
Interrupted transfers resume and retry instead of starting over, which helps on unstable connections.
Manual fallback GUI
A configuration screen lets the user set Java options by hand when automatic configuration fails.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Modpack first launch
A modpack that ships Forge 1.12.2 with Cleanroom can rely on the relauncher to prepare Java and the loader on each new machine.
Mixed hardware
Players on x64 Windows or Linux machines and on ARM64 or Apple Silicon Macs can use the same instance without manual Java selection.
Who it’s for: Modpack authors and players who run Forge 1.12.2 instances with the Cleanroom Loader and want the first-run Java and loader setup handled automatically.
Questions
Does Improved Cleanroom Relauncher need to be installed on the server?
Which Cleanroom Loader release does the relauncher use?
Where are Java runtimes stored after setup?
In the catalog
Improved Cleanroom Relauncher is one of 36,990 Utility mods on ModsFinder, and one of 14,575 Utility mods for Forge. 2,920 mods support Minecraft 1.12.2.
More from Bruv Network
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What the author says
Relaunches a Forge 1.12.2 instance with Cleanroom Loader, with a streamlined first-run experience and automatic Java setup. Features - Automatic Java download and setup - Configurable major version (default: 24) - Configurable distribution (default: Adoptium) - Cross-platform and arch-aware - Windows: x64, ARM64 …
Official listing
- Modrinth page
- modrinth.com/mod/improved-cleanroom-relauncher
- Owner
- Bruv Network
- Published
- 2025-08-28
- Updated on Modrinth
- 2026-03-16
- Facts verified
- 2026-10-15