Minecraft Failed to Reload Core Shaders (could not reload shaders)

What the log looks like

java\.lang\.RuntimeException: could not reload shaders
java\.util\.concurrent\.CompletionException: java\.lang\.RuntimeException: could not reload shaders

How to fix it

1. Disable active resource packs that modify fonts, UI, or core shaders; if the game crashes on launch, open options.txt in your Minecraft folder and set resourcePacks:[] to reset them.
2. Open logs/latest.log and check the 'Caused by:' lines directly below 'could not reload shaders' to see the exact shader file path or mod namespace that failed to parse.
3. If you use Sodium or Iris alongside heavy rendering mods like Immersive Portals or Physics Mod, remove those add-on mods or switch to versions explicitly compatible with your Sodium/Iris version.
4. If you are creating a custom resource pack, compare your assets/minecraft/shaders/core/ JSON and GLSL files against the default files from your exact Minecraft version to remove deprecated uniforms.

Check your own log