Kaspersky Total Security 2021 version 21.3.10.391 for Windows was a high-water mark for consumer cybersecurity. It successfully argued that you don't need to sacrifice CPU cycles for safety. The inclusion of a Password Manager and Backup tool made it a true "total" package, eliminating the need for separate subscriptions.
For those running legacy hardware on Windows 10 (and who cannot upgrade to Windows 11), this version, provided you can manually update the virus definitions, remains a viable fortress. However, for modern PCs, you should seek the latest version (e.g., Kaspersky Plus 2025) to ensure protection against today's AI-generated malware and ransomware gangs.
Final rating (in its 2021 context): 9.2/10 Final rating (for use in 2026): 3/10 (only due to outdated engine, not quality) Kaspersky Total Security 2021 21.3.10.391 for W...
The build number 21.3.10.391 corresponds to a mid-cycle update for the 2021 lineup.
Kaspersky Total Security 2021 (build 21.3.10.391) is a mature, full‑featured consumer security suite that combines layered malware protection with privacy, identity, parental‑control, backup/encryption and utility features. Strengths: strong detection history, broad feature set, useful extras (VPN, password vault, parental controls). Weaknesses: potential compatibility/driver issues on some Windows builds, UI complexity for nontechnical users, larger resource footprint than lightweight alternatives. Recommendation: good for families or users who want an all‑in‑one suite; less compelling if you prefer minimal system impact or only basic antivirus. Kaspersky Total Security 2021 version 21
The installer offers a quick or custom install. During testing, the default installation proceeded smoothly without forced third-party toolbars. A mandatory system scan starts after installation, which can be postponed.
One caveat: The 2021 version occasionally prompts to upgrade to a newer edition, which some users may find intrusive.
Kaspersky Total Security build 21.3.10.391 was a specific release of the 2021 product line. It functioned as the company’s flagship premium security suite, offering multi-layered protection, a firewall, parental controls, and password management. For those running legacy hardware on Windows 10
As of 2024, this specific version is considered outdated. It has been succeeded by the "Kaspersky Standard/Plus/Premium" product line (builds starting with 21.12+ and eventually rebranded). Continued use of this version poses security risks due to the lack of current threat definition updates and support.