A file created by an application for its own purposes. In the days of limited main memory, temporary files were the only way to store large amounts of interim data that the application was generating. Today, main memory is often used instead. Temporary files typically have a .TMP or .TEMP file extension, but any naming convention might be used. Not Always Deleted An application is responsible for deleting its temporary files; however, such files often remain on disk if the computer crashed, and the program was not closed properly. See temporary folder and temporary Internet files.