Can't get my Puff Pastry shells to rise

The Pepperidge Farm site offers some tips for baking related to the rise:

• Always preheat your oven for a minimum of 15-20 minutes before baking, because Puff Pastry depends on even heat to rise and puff. Place pastries 1 inch apart.

• If you want a flaky thin and crispy pastry that's not very puffy, prick the unbaked Puff Pastry all over with a fork, which lets steam escape while baking.

• To create a tart with an extra puffy crust: take a knife and score two lines around the edge, then prick the area inside this border with a fork.

I would begin by verifying that these tips were observed. Also, I would verify that your oven bakes consistently (i.e. no hot/cold spots). Preheating can be very helpful in resolving this. Also, you can put in a pizza stone or other heat regulating product, and monitor the temperature with a probe thermometer in water in different areas of the oven.

If your fridge is cold then overnight may not have been long enough, and it could be that some were still frozen. I'd say that was the most likely culprit.

My mother made these for years, and I make them now, and we NEVER thaw them. We always cook them from a frozen state, and they come out fine. I've found that the only time they don't rise properly is when they're old, so check the expiration/best by date.