Texture Jumps Around After Unwrap? Every time I unwrap my mesh, the texture jumps around!

Before Unwrap (look at the label):



After Unwrap:


As you can see, the label on the bottle has jumped around. I can't bake it like this. When I try to move vertices around and get the label back in the right place, I destroy the arrangement of the UV map.

What can I do to keep all the textures in place after unwrap? I tried both the smart unwrap and the lightmap pack unwrap, and the position of the label jumped on both.
In the UV editor you can pin selected vertices from the UV editor menu UV -> Pin or press the P key.

You can also unpin them from the same menu or Alt + P.

There are also other ways to give finer control, for example you can create seams in your UV map effectively cutting it into parts that unwrap nicely.

Too long a discussion for here, but in mesh edit mode you can mark edges as seams, then when you unwrap it will be more forgiving.

You would still need to pin vertices if unwrapping a second time, but gives you more options.