Avoiding head halo.

[Dundridge Dreadlow]

Even though your avatar may look normal to you, some people may complain of seeing a weird and disturbing halo around your avatars head. This is caused by an issue with avatar hair and shaders, and can easily be avoided by wearing what is generally known as a "bald cap" with a non-invisible texture.

The creator of the bald cap should make sure there is an actual texture(ie, not invisible) on the hair ("default" will do). If the creator does not want to see Linden hair on the avatar, they should reduce the hair volume to zero and NOT use an invisible texture

For more information see this thread Hair "Halo"