While most e-mail clients allow users to file messages into folders, the process they must go through to file each message is often tedious and slow. For each message, the user must first decide which folder is most appropriate. Then, the user must inform the e-mail reader of that choice by selecting the appropriate icon or menu item from among what is typically a set of several dozen choices. The combined effort of choosing a folder and conveying that choice to the application often discourages users from filing their mail, resulting in unmanageable inboxes that contain hundreds or even thousands of unfiled messages. SwiftFile encourages users to file their mail by simplifying the task. Using an adaptive classifier, it predicts the three folders that are most likely to be appropriate for a given message and provides shortcut buttons that permit the user to effortlessly file it into a predicted folder. For typical users, SwiftFile’s predictions are accurate over 80% to 90% of the time, resulting in a substantial reduction in the time and cognitive burden required to file messages.