The Trend Micro scan engine uses an external data file, called the virus pattern file, to keep current with the latest viruses and other Internet risks such as Trojans, mass mailers, worms, and mixed attacks. New virus pattern files are created and released several times a week, and any time a particularly pernicious risk is discovered.

All Trend Micro antivirus programs using the ActiveUpdate feature (see ActiveUpdate for details) can detect whenever a new virus pattern is available at the server, and can be scheduled to automatically poll the server every hour, day, week, and so on, to get the latest file.

If multiple pattern files exist in the same directory, only the one with the highest number is used. Trend Micro publishes new virus pattern files on a regular basis (typically several times per week), and recommends configuring a hourly automatic update on the Administration → Updates → Components Updates screen. Updates are available to all Trend Micro customers with valid maintenance contracts.