Pattern feature

Is anyone else having issues with using the Pattern feature for copying components? It seems like every other time I use it, I blow it’s mind and the program locks up. I can understand if I tried to make a million of something, but I tried to make the image below. I had a tray with 50 basic shape rectangles and I wanted one on each shelf (27). It doesn’t seem like that should crash this program.

I guess I should remember to save my work, before I try this again.