when i try to uv unwrap my mesh , blender hangs and become unresponsive, why? I am new to blender, when i try to uv unwrap my mesh, blender hangs and become unresponsive. the mesh has nearly 35000 faces. it is a subdivided sphere which i used for sculpting. 
when i uv unwrap a simple cube , it works fine. is there a workaround for this, or a better alternative way to apply texture?
Potential Solution: Smart UV Project



Although I've never tested this method on a UV Unwrap task that has crashed Blender, I've found that using the 'Smart UV Project' option is much faster using the normal 'Unwrap' function.

I found this when unwrapping the mesh of an ANT Landscape body, where it would take several unresponsive seconds before Blender processed the unwrap using the regular unwrap function. 
However, when I unwrapped again using the 'Smart UV Project' option (with the default parameters), it was almost almost instantaneous.

I know this is a pretty old post but I'll leave this here just in case anyone finds it and gets help from this answer. (Hope I haven't broken any community forums by 're-opening' an 'archived' thread.)