This article serves as a definitive guide for users who are currently running this version, need to reinstall it, or are comparing its legacy features against modern alternatives. Kaspersky Total Security (KTS) is the flagship consumer suite. Version number 21.3.10.391 is a specific patch (patch 'a' / 'b') release of the 2021 product line. It was signed and released in late 2020 but remained the standard for most of 2021. Unlike the modern "Kaspersky Standard" (which replaced KAV/KIS) and "Kaspersky Plus" (which replaced KTS), this version strictly used the traditional interface—a dark green and white theme with a dashboard-centric layout.
This version will install on Windows 11, but due to Microsoft's security changes (Virtualization-Based Security, Hypervisor-protected Code Integrity), you may experience performance glitches or a warning that the software is "Not fully compatible." How to Download & Install (Legacy Guide) Because Kaspersky no longer officially hosts 2021 versions on their main site (they redirect to the 21.13+ installer), you must obtain the 21.3.10.391 build from trusted archives or offline installers. Kaspersky Total Security 2021 21.3.10.391 for W...
However, cybersecurity is a forward-moving field. In 2025, using any antivirus version from 2021 is akin to driving a 2021 car with 2021 tires—you might get around town, but you won't stop as quickly in the rain. If you have an active license, . If you have a perpetual license, consider using it only on air-gapped or legacy machines. This article serves as a definitive guide for