Wrong mod loader

Failed to read accessWidener file: Namespace (named) does not match (intermediary)

What it looks like in the log

java.lang.RuntimeException: Failed to read accessWidener file from mod iris

How to fix it

  1. Open your instance's 'mods' folder and find the mod named in the error message (for example, 'iris').
  2. Check the exact filename of that JAR—if it says 'neoforge', 'forge', or '-dev' (such as 'iris-neoforge-1.8.10+mc1.21.5.jar'), delete it from your mods folder.
  3. Download the 'Fabric' version of that mod (such as 'iris-fabric') that matches your exact Minecraft version from Modrinth or CurseForge.
  4. Verify that all other mods in the folder (such as Sodium) are also the Fabric versions and not NeoForge/Forge builds, then relaunch the game.
LoadersFabric
SeverityStops the game
CategoryWrong mod loader

Check your own log

Related errors

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