Kaspersky Total Security 2021 21.3.10.391 For W... -

Warning: If you are reading this article to download actual version 21.3.10.391 for daily use in 2026, do not do so unless it is for an air-gapped computer.

However, for IT historians or users running an offline Windows 10 LTSC machine, this version represents the pinnacle of classic, non-cloud-dependent security.

Critical Warning: Using version 21.3.10.391 in the present day is not recommended. Kaspersky Total Security 2021 21.3.10.391 for W...

Product Transition: Kaspersky has largely retired the "Total Security" branding in favor of "Kaspersky Premium." Users on build 21.3 are strongly advised to migrate to the newer product line to ensure gapless protection.

If you are currently running this version, ask yourself:

Stay on 21.3.10.391 if:

Upgrade immediately if:

If you are installing version 21.3.10.391 on an old machine, these are the requirements: Warning: If you are reading this article to

| Component | Minimum Spec | | :--- | :--- | | OS | Windows 7 SP1 (with ESU support), Windows 8.1, Windows 10 (20H2) | | RAM | 1 GB (32-bit) / 2 GB (64-bit) | | Disk Space | 1.5 GB free | | Processor | 1 GHz | | Screen | 1024 x 768 (for the GUI to render properly) |

Warning for modern users: 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." However, for IT historians or users running an