Unable to find styles in GameSkin to Repaint

I’ve created a GUISkin to handle a simple change of images for my scrollview and scrollbar thumb. But I am getting these errors:

Unable to find style ‘scrollviewthumb’ in skin ‘GameSkin’ Repaint
UnityEngine.GUI:BeginScrollView(Rect, Vector2, Rect, GUIStyle, GUIStyle)

Unable to find style ‘scrollviewupbutton’ in skin ‘GameSkin’ Repaint
UnityEngine.GUI:BeginScrollView(Rect, Vector2, Rect, GUIStyle, GUIStyle)

Unable to find style ‘scrollviewdownbutton’ in skin ‘GameSkin’ Repaint
UnityEngine.GUI:BeginScrollView(Rect, Vector2, Rect, GUIStyle, GUIStyle)

When I looked inside the untouched GUISkin I noticed that the normal image for vertical scrollbar thumb was labeled “Missing Texture”

I’ve replaced it with my own art but it continues to print the warning messages and will not draw my replacement icons. Is this a Unity bug? How can I fix GameSkin?

On your skin, at the very bottom, is a Custom Style array, you have to create at least 1 (size 1) and then name it scrollviewdownbutton.

Hope it helps.