Material doesn't have a color property '_Color'

Hi, my console write me this error:
Material doesn’t have a color property ‘_Color’
UnityEngine.Material:get_color()
material_switch:Start() (at Assets/Scripts/CS script/material_switch.cs:14)

But i dont know what is it.
Any idea how to fix it?
here is my source code:

using UnityEngine;
using System.Collections;

public class material_switch : MonoBehaviour {
	
	public Material original_material;
	public Shader original_shader;
	public Color original_color;
	public Material edit_material;

	public void Start () {
		original_material = transform.renderer.material;
		original_shader = transform.renderer.material.shader;
		original_color = transform.renderer.material.color;
	}

	public void restoreMaterial() {
		transform.renderer.material = original_material;
		transform.renderer.material.color = original_color;
		transform.renderer.material.shader = original_shader;
	}

	public void saveMaterial() {
		original_material = transform.renderer.material;
		original_shader = transform.renderer.material.shader;
		original_color = transform.renderer.material.color;
	}
	
	public void setEditMode() {
		transform.renderer.material = edit_material;
		transform.renderer.material.shader = Shader.Find ("Diffuse");
		transform.renderer.material.color = new Color32(72,114,19,255);
	}
	
	

}

Thanks

Kind regards
Thomas

Not all shaders support main color. First check the material. You should see a color selection tool on the right and on the left you will usually see “Color” or “Main Color”. If your material does have a color selection box, then it does not support color. If you have a selection box, open the shader and see if that color is named _Color.

Only a fraction of the shaders that ship with Unity have a _Color property.

As many will still bump into this thread (and no threads
on Unity issues will ever be old):

-Just try using some of shaders under: Particles - “Additive”
or any of them, in the particles-“additive” list
of shaders …