One way to do this is to create a new project, then start copying resources from the old project into the new project one by one. You don't actually have to build the project, you just need to add a resource, and then switch back to IB to see if it crashes. Once you find the resource that crashes IB, please let me know what type (JPEG, PNG, etc) it was, and if you notice any problems when opening it in Preview. We've seen some instances of strange resource headers in images and stuff causing syncing issues with IB, so please be sure to let us know what you find.