Automatic updates are another need in virus protection. Both the virus database and the program itself can be updated automatically. The updates are incremental, with only new or missing data downloaded: thus reducing the transfer heavily. The typical size of a virus database update are tens of KB; program updates are typically in the hundreds of KB range.

If your Internet connection is persistent, the updates are performed completely automatically at fixed time intervals. If you connect to the Internet only occasionally, avast! watches your connection and tries to perform the update when you are online.

Having an up-to-date virus database and antivirus program is the most certain way to protect your computer.