I move an elbow from my IK bone and the other arm moves too. Why is that? how can i solve it?
Help =([![enter image description here](https://i.stack.imgur.com/ZMiDL.png)](https://i.stack.imgur.com/ZMiDL.png)
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Your bone is called Bone.011 so it's not getting mirrored properly. You need to make sure the bones have names like hand.l, hand.r (for the other side) and so on.

For the automatic weighting, you can just redo it by reparenting the mesh to the armature with automatic weights.

Another thing that can break the automatic weights are incorrect normals, so you can go into edit mode, select all vertices and Recalculate Normals to make sure they are good.
When you link your armature to your mesh using automatic weight, sometimes the weight is applied wrongly to the mesh. It could be that you did not apply your mesh's scale.

1. In object mode, Hit `Alt``A`
2. Select "Scale" from the Drop down menu.

You could also go to the vertex group control panel and manually remove those vertices that aren't suppose to be affected by the bone.