I got your message. You're experiencing what looks like a "memory leak." That can happen sometimes with either a third party plug-in or a project corruption. Do you have any plug-ins working in your current sequence? If so, update or remove them from clips they are applied to. If you don't have any suspect plug-ins, try fixing a project corruption by creating a new project, and then importing the contents of the legacy project into the newer one. I hope one of these pieces of advice helps you. Please come back and let us know what happens.