About Real-time Scan
Real-time scanning provides constant protection against viruses. With real-time scanning turned on, you reduce the chance of your computer becoming infected. Because it is so powerful (and because it operates imperceptibly in the background), we recommend you always keep real-time scanning enabled.
The real-time scanner checks files for viruses whenever they are used, for example each time a file is opened, copied, moved, saved, compressed or decompressed, downloaded from the Internet, and, in the case of email attachments, read.
See also:
Selecting Real-time Scan file types
Adding Real-time Scan tile types