Unsafe World Random Access Detector
This is a mod that detects unsafe off-thread world random access, helping to find causes of "Accessing LegacyRandomSource from multiple threads" crash.
Screenshots
About this Mod
Unsafe World Random Access Detector
This is a mod that detects unsafe off-thread world random access,
helping to find causes of "Accessing LegacyRandomSource from multiple threads" crash.
This is useful for finding the cause of mysterious crashes with Accessing LegacyRandomSource from multiple threads.
This is not a fix for the issue, but it will help you find the cause of the issue.
Note: If you are already using C2ME, this mod is not needed (but won't crash if used together anyway).
Available Versions
How to Install Unsafe World Random Access Detector on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (26.2).
Install Mod
Open the mod browser in the dashboard and search for "Unsafe World Random Access Detector". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
26.2, 26.1.2, 26.1.1 (+26 more)
Server-side
~ OptionalRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Unsafe World Random Access Detector server crashes on startup – what to do?
Most common cause: wrong fabric 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 (26.2). You can switch loaders with one click in the panel.
Is Unsafe World Random Access Detector compatible with fabric and forge and neoforge?
Unsafe World Random Access Detector officially supports fabric, forge, neoforge for Minecraft 26.2, 26.1.2, 26.1.1. Note: Forge and Fabric mods are NOT cross-compatible – pick one loader and stick with it. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Unsafe World Random Access Detector – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Unsafe World Random Access Detector 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.
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Rent Modded Server
Install Unsafe World Random Access Detector with just one click on your server.