Hi Steven, Can you tell us which platform you're on, and the output of pharo --version Cheers, Alistair On 7 Apr. 2017 12:48, "Steven Rémot" <steven.remot@gmail.com> wrote: Hello everyone, I'm new to pharo, and was writing a simple 2D game with Athens for rendering to practice a bit. I'm loving the environment so far, developing the game while it's running is really enjoyable :-) . However, when the game is running, the pharo image will freeze at a random time. Alt-. doesn't make my image back to normal, the only solution I found is closing my image and opening it again, until the next freeze... I don't really know what to do to investigate this bug, there is no output from pharo about this. The only thing I thought about is starting from a fresh image, importing my code and running it again to ensure it wasn't some messy state in the image I was using, and it froze even when running my code from a fresh image. What can I do to debug it? Do you need more information to give me a direction? Just in case you need it, here is the source: https://www.dropbox.com/s/ pfn7ccw27i4nqr7/Creakout-debug.st?dl=0 Thanks, Steven Rémot