Do I Need to Update My Antivirus?

I received the following question from a reader last week:

"My AVG keeps telling me it is downloading updates.  Is it normal for it to always be updating?"

Yes, it is normal for an antivirus program like AVG to be updated regularly.  More on that in a minute.  However, I first want to address one other issue.  If it seems like your antivirus is constantly updating, it might be a good idea to make sure that updates are actually being downloaded and installed.  To check this, open your antivirus software from either the Start Menu or the Notification Tray (near the clock).  Then, search for a place where it lists the date of the last update (it could be in a variety of places depending on what software you are using).  If it is more than 24-36 hours old, there is probably something not working properly with the update process.  If you cannot quickly solve the issue, I would recommend uninstalling and reinstalling your antivirus.

Now, back to why antivirus updates are important.  Antivirus software relies on files (called "definition files") that provide information on the latest threats detected.  These files tell the software what clues will be left on the computer for each type of infection.  This makes these programs excellent at detecting threats that they know about, but it means that a new threat (not in its definitions) can easily escape detection until the file has been updated with its information.  While software is getting better at detecting threats based on behavior, detection based on definition files is still much better.

In order to keep your system safe, antivirus software will update regularly.  Some software will be programmed to only update once per day, and others will update anytime it is connected to the internet and a newer file is available.  Most antivirus software publishers will release multiple updates each day, and most will update as soon as it realizes a newer file is available.  Fortunately, most of these updates are small and need very few resources.

I do not know of any antivirus programs that allow you to shut off automatic updates, but I definitely do not recommend doing this.  Turning off automatic Windows updates is generally not a good idea, but turning off automatic antivirus updates is even worse.  Not keeping your antivirus up to date is almost as bad as not having an antivirus.