In this section, you can define a folder into which infected files will be moved automatically when they're found.
To do so, click the "Set Quarantine Folder…" button and navigate to a folder on your hard drive where you want infected files put. You can then enable and disable the option by clicking the checkbox to the left of the button. Once a folder has been set, you will see it listed beneath the checkbox. It cannot be unset, however, it can of course be changed.
Please be careful with this option - if a message in your email mailbox is infected, this option has the potential to move your entire mailbox (with the exception of Apple Mail and some others) away from where it should be, rendering your email missing and inoperable! In most cases, it can be moved back to where it should be, but on the whole it's not an easy task and I regret that I am unable to explain how to do this. If you find yourself in this situation, my web forums may provide some useful advice.