Thanks! I worked with Local IT Tech Support this afternoon. They uninstalled and re-installed the video driver, but, even then, sometimes it printed the lines, and sometimes it didn't. What I've been doing is saving the whole diagram as a PDF first so I can print to the Plotter printer more easily. However, the lines don't show up in Visio layers, Print Preview, or the PDF, and sometimes they will print, and sometimes they won't. They seem to usually be attached to an edge of the drawing. Here's another example. Any other thoughts? Suggestions?