Why do materials sometimes show up as bright magenta in the Unity Editor?

When materials appear as bright magenta in the Unity Editor, it typically indicates that the shader associated with that material is missing from the project. This is a common visual cue in Unity, as the bright magenta color is a placeholder that signals developers to check for issues with their shaders.

Shaders are integral to rendering materials in Unity, defining how surfaces interact with light and appear visually. If a shader is deleted, moved, or otherwise becomes inaccessible, the material cannot render correctly, leading to this bright magenta display. This serves as a helpful error indicator for developers to identify the source of the problem, prompting them to either re-import the missing shader or replace it with an existing one.