This is just C3d's way of letting you know you are getting to much accomplished or that you are being to productive.
Kidding aside: This happens from time to time, for a variety of reasons. If it happens more than once in short order, the drawing more than likely needs to be recovered and purged. If it continues producing such errors it may need recreating. If many drawing crash frequently you may need to reinstall the software or possibly even upgrade your hardware, graphics card mainly but possibly memory and/or cpu or other components.
