About Unsafe World Random Access Detector
From ModrinthThis is a mod that detects unsafe off-thread world random access, helping to find causes of "Accessing LegacyRandomSource from multiple threads" crash.
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).
Highlights
From source dataGame versions
Supports 30 Minecraft versions, the newest being 26.3.
Loaders
Runs on Fabric, Forge and NeoForge.
Footprint
Rated a light load on a server.
Unsafe World Random Access Detector on Nxeon
From our catalogue- One-click install
- Supported on Nxeon Minecraft servers. We download it from Modrinth, place it, and restart the server.
- Server side
- Optional on the server
- Server type needed
- Fabric, Forge, NeoForge
- Server load
- light
- Smallest plan we suggest
- Minecraft — 2 GB (2 GB RAM). This follows our own load rating above, not a benchmark.
- Latest build
- 1.1.4+neoforge, released 2026-10-05
Game versions by loader
| Loader | Game versions | Newest |
|---|---|---|
| Fabric | 1.19 to 26.3 (30 versions) | 26.3 |
| NeoForge | 1.21 to 26.3 (17 versions) | 26.3 |
| Forge | 1.19 to 1.21.1 (13 versions) | 1.21.1 |
From 7 recorded builds of Unsafe World Random Access Detector.
Recent builds
| Build | Released | Game versions | Loaders |
|---|---|---|---|
| 1.1.4+neoforge | 2026-10-05 | 1.21 to 26.3 (17 versions) | NeoForge |
| 1.1.4 | 2026-10-05 | 1.19 to 1.21.11 (24 versions) | Fabric |
| 1.2.0 | 2026-03-24 | 26.1 to 26.3 (6 versions) | Fabric |
| 1.1.3+neoforge | 2025-05-26 | 1.21 to 1.21.5 (6 versions) | NeoForge |
| 1.1.1+neoforge | 2024-09-29 | 1.21 to 1.21.1 (2 versions) | NeoForge |
| 1.1.1+forge | 2024-09-29 | 1.20.6 to 1.21.1 (3 versions) | Forge |
Run Unsafe World Random Access Detector on a Minecraft server
Pick a server or deploy a new one above; it is installed in one click.
What kind of mod it is
From the catalogGameplay & overhauls
New mechanics, content and overhauls that change how the game plays.
Works on a server
From source side supportModrinth lists server-side support for Unsafe World Random Access Detector as optional: it can run on a server, but isn’t required there.
Compatibility
- Game
- Minecraft
- Loaders
- FabricForgeNeoForge
- Runs on
- Serveroptional on the server
- Game versions
- 26.3 and 29 earlier
Verified at the source
- ✓ModrinthOfficial listing, checked 2026-10-05Open ↗
- ✓Authorishland, as published on Modrinth
- ✓LicenseMITFree
