Why is my old game showing up Pink in Unity V5

I created a game about a year ago. Now if I open it in the updated unity 5 all the objects appear pink. Why and is there a fix for it?

Thanks

 

Maybe they are missing materials?
Or shader is not working, any errors in the console window?

 

yea, pink is the default for shader missing or errors. Try updating your shaders on the pink objects. I have found that some older custom shaders don't work under 5.