PRovide screenshots, proper system and version info, details about your effect settings. It can only work this way.
As Mylenium says, screenshots are necessary to troubleshoot something like this.
My guess based on limited information so far is that your force radius is set to not encompass the entire image/object that you want to shatter.
I strongly recommend watching Brian Maffitt's video linked to from here:
Put shatter in wireframe mode, look at the force field. Did It include all of the layer? What are your physics settings? If pieces are not moving you have to change something about the setup. There are about a zillion combinations of settings for shatter, without seeing which are not at the default setting it is impossible to give you any better idea than I just did.
If my suggestion did not solve your problem then select the shatter layer and press the U key twice to reveal all changed properties, then send us a screenshot showing the timeline and the comp at the point where you are having problems.
Depending on the custom map settings, there are some alpha properties that Shatter will not affect.
Thanks to everyone who answered! I adjusted the force radius, and it worked normally.
I'm so sorry for bothering you, I'm just a newbie at AE.