What recipe do you use ?
My recipe has changed over the years but I have come up with a standard as basis for all my recipes.
A lot of books don’t touch on how to grind your almonds when in fact this is very important to your end product. When using a food processor, try grinding the nuts a bit first and then put your powdered sugar in and then grind further. I started with a home food processor and I always had to sift.