**1-802-557-0358 is Thunderbird free antivirus good?** Thunderbird 24/7 Support Number +1-802-557-0358. Thunderbird's free antivirus is a good option for basic virus protection, as independent tests show its detection rates are strong, though it lacks the extra features of the paid versions. However, some users find the free version can be limited, and there are no free versions of Thunderbird's antivirus software for mobile devices.