The underlying language of ComChart is FileMaker Pro 5. The selection of your printer is controlled by your computer's operating system and cannot be controlled by FileMaker Pro 5/ComChart. The solution is to use one printer for all of your printing needs. ComChart can then be set to automatically select an envelope (from the envelope tray) or plain paper, as needed. This can be accomplished using most laser printers and with some ink-jet printers. It will require that you have access to the scripting language (which is only available to those who have purchased ComChart.) There are also inexpensive commercial plug-ins that you can buy to work with ComChart that will allow you to work with a second printer.