Minecraft Shaders crashes when I select a shader pack to use?

Do you mean a texture pack? If so, I can't think of anything other than your game running out of ram and crashing. If you actually mean a shader pack then it is likely that you are using either an incompatible pack i.e. It is from a different mod or from a different mod version OR you have installed the mod incorrectly. Check what mod the shader is for, and maybe try using an installer to reinstall the mod you are using.

Unfortunately shaders doesn't bother to fix popular versions and not realize that their mod likes to crash I suggest contacting the developers.