You need to set up default printer in your operating system as MATLAB accesses the defaults to figure out where to print, if no defaults are found, it tries to search for printers.
The output of " printopt " should show if you have a default printer set up. For Windows, I believe it uses the default printer set up in Control Panel -> hardware and sound -> Devices and Printers. For Mac and Linux , it uses the output of
lpr -r
Have a look at the printopts.m file to get a better idea of how MATLAB is handling this.
