Sometimes Unity displays pink colour instead some things.

Unity Engine
1

Pink colour replaces normal displaying of Particle Renderer.
Like below:

2

Are you getting Shader Errors in the Console?

If a Shader can’t compile it’ll replace it with a basic pink texture, also it could be that there is no available fallback for the shader you are using compared to your Hardware (Shader requires Shader Model 3, your hardware doesn’t support it).

3

Sometimes it is just because the texture is missing from the material.