Trend Micro™ Security (for Macintosh) has two scan types; Real-time Scan and Manual/Scheduled Scan.
Real-time Scan: Real-time Scan is a persistent and ongoing scan. Each time a file is received, opened, downloaded, copied, or modified, Real-time Scan checks the file for malware.
Manual Scan: Manual Scan is an on-demand scan. Use the Manual Scan screen to configure scan options and scan for malware. Manual Scan also eradicates old infections, if any, to minimize reinfection. Manual Scan starts immediately and scans all the specified files. The duration of the scan depends on hardware resources and the number of files. During a Manual Scan, Trend Micro™ Security (for Macintosh) takes action against threats according to the actions set by the administrator or User. To stop the scan, click Stop when the scan is in progress.
Scheduled Scan: Scheduled Scan is similar to Manual Scan except that Scheduled Scan checks all files at the configured time and frequency. Use Scheduled Scan to automate routine scans on computers.