I'm applying a shatter effect to a background image to make it looks like it explodes. It worked great yesterday but today the shatter is starting already shattered, instead of together. I don't want this effect, I want it to start unshattered then explode. Is there a setting for this or is the effect defective now?
Mess with the Influence Sphere setting.
if I had to guess, I would say that your shatter layer is moved in time or trimmed later. the shatter effects starts at the original source of your layer. it means that if you trim your layer later in time or move your layer back in time, you could see the effect only after it has done it's thing. to make sure, press twice on the layer and you will be opening the footage layer that is the layer content in the context of the layer itself.
this is how it would look if you trimmed the layer in the timeline.
you should move the in point to the beginning of the original in point of the layer.
the other case could be that your layer is starting before the start time of your timeline. like this:
you should move it to the start. short cut Alt+Home.
if this is not the case, show us a screenshot or two of your full Ae interface so we can see what's going on. also share your full Ae version and Os.