Why is a skin only applying to the right half of my mesh avatar and the other half disappears?

[loganoats]

When I drag the skin from my inventory onto the rezzed mesh avatar it applies exactly to only the right half of the avatar and the other half disappears, any ideas?

[Lindal Kidd]

You are not meant to apply a classic skin to a mesh avatar!  Only wear skin textures (the things with the inventory symbol of a spreadeagled body) on your classic avatar body.

Skin textures are applied to mesh avatars with an "applier", a little HUD.  The applier is obtained (usually for free, or a low price) from the skin creator, and is specific to a certain brand of mesh avatar.  So if you have a Maitreya mesh body, you buy the Maitreya skin applier for your favorite skin tone.