Understanding Printfil and the Risks of "Top" License Keys Printfil is a popular Windows utility that allows legacy applications—such as DOS, Unix, and Linux programs running in emulation—to print to modern USB, network, PDF, and IP printers. Because it is a paid, proprietary software, many users search for terms like "printfil license key top," "Printfil crack," or "Printfil registration code" to bypass purchasing a legitimate license.