This turns out to be a problem with how the Select2D job works. When plotting the particles you see in the “Overview” tab, we read in the entire particle stack because we assume it came from one micrograph (so not too many). In this case, we might have to be less lazy and only open the particle images we need so we don’t use the entire system’s memory! For the time being, is it possible if you can split up the particle stack into smaller .mrc files? We’ll fix this and update this post when it’s done. Thank you for reporting!