Kaspersky Total Security version 21.3.10.391 for Windows is an all-in-one protection suite designed to provide comprehensive defense against malware, ransomware, and online privacy threats. As of 2026, while this version remains functional on many systems, Kaspersky has transitioned its core consumer offerings to a new tiered structure (Standard, Plus, and Premium) with updated interfaces. Core Security Capabilities
This version includes the high-performing malware engine consistently recognized by independent labs.
Real-Time Antivirus: Continuously scans for viruses, Trojans, rootkits, and spyware.
Automatic Exploit Prevention: Specifically for Windows, this feature identifies network exploits like EternalBlue that can crash operating systems.
Anti-Ransomware: Monitors for behavior typical of ransomware to block attacks before files are locked.
Two-Way Firewall: Manages both incoming and outgoing network requests to prevent unauthorized access. Privacy and Premium Features
The "Total Security" tier distinguishes itself from standard antivirus by including advanced privacy and family tools: Kaspersky Total Security 2022 updates
This paper provides an overview of Kaspersky Total Security 2021 (Version 21.3.10.391), focusing on its features, system requirements, and the specific improvements introduced in this release for Windows users. Overview: Kaspersky Total Security 2021 (21.3.10.391)
Kaspersky Total Security 2021 is a high-tier security suite designed to provide comprehensive protection against a wide range of digital threats. Version 21.3.10.391 (also known as MR3) is a stable release that focuses on enhancing web security, streamlining technical support, and improving the overall user interface. 1. Key Features and Capabilities
Multi-Layered Protection: Combines traditional signature-based detection with advanced behavioral heuristics to block both known malware and zero-day threats. Kaspersky Total Security 2021 21.3.10.391 for W...
Web-Antivirus Enhancements: In version 21.3.10.391, notification texts for phishing and potentially dangerous sites were improved. If HTTPS traffic scanning is disabled, protection is maintained via the Kaspersky Protection browser extension. Privacy & Identity Tools:
Safe Money: A hardened browser for secure online banking and shopping.
VPN Secure Connection: Encrypts data and masks IP addresses (limited daily data unless upgraded).
Password Manager: Stores and syncs credentials securely across devices.
Webcam Protection: Prevents unauthorized access to the device's camera.
Family Safety: Includes a full version of Kaspersky Safe Kids, offering parental controls such as screen time limits, social media monitoring, and GPS tracking.
Performance Optimization: Features a Gaming Mode that pauses notifications and heavy scans to ensure maximum system performance during play. 2. Technical Specifications & Requirements
Version 21.3.10.391 is optimized for performance on modern Windows environments but remains compatible with older systems. Minimum Requirement Operating System Windows 7 (SP0 or later), 8, 8.1, 10, and 11 CPU 1 GHz or higher (SSE2 instruction set support required) RAM 1 GB (for 32-bit OS) or 2 GB (for 64-bit OS) Free Disk Space 1500 MB (1.5 GB) Other
Internet connection for activation and updates; .NET Framework 4.0+ 3. Notable Improvements in Version 21.3.10.391 Kaspersky Total Security version 21
The MR3 (Maintenance Release 3) update brought specific functional refinements: Kaspersky Total Security 20 System Requirements
In today's digital landscape, keeping your personal data and hardware safe is more critical than ever. Kaspersky Total Security 2021 (specifically version 21.3.10.391) remains a benchmark for Windows users seeking a "set-it-and-forget-it" safety net. This version is designed to handle everything from stealthy ransomware to identity theft, providing a multi-layered shield for your PC. Advanced Threat Detection and Malware Defense
The core of the 21.3.10.391 update is its refined scanning engine. It doesn't just look for known viruses; it uses behavioral analysis to spot suspicious activity. If a program starts encrypting files unexpectedly—a classic sign of ransomware—Kaspersky intercepts the process and rolls back any changes made to your data. This version also features an improved "Gaming Mode," ensuring that scheduled scans and notifications are paused while you are in full-screen mode, preventing lag during gameplay. Privacy Features and Identity Protection
Beyond standard antivirus, Total Security 2021 offers a suite of privacy tools that are particularly useful in the era of remote work. The Webcam Protection feature alerts you whenever an application attempts to access your camera, preventing "cam-fecting" by hackers. Additionally, the Safe Money browser extension creates a hardened, isolated environment for online banking and shopping. This prevents keyloggers from capturing your credit card details and protects your financial sessions from DNS spoofing. System Optimization and Ease of Use
Many security suites are notorious for slowing down Windows, but Kaspersky 21.3.10.391 is optimized for low resource consumption. It includes a "PC Cleaner" that identifies junk files and unused applications that might be clogging your system. The interface is intuitive, featuring a clean dashboard that highlights your current security status and provides one-click access to the password manager, file shredder, and parental controls. For families, the Safe Kids feature allows parents to manage screen time and filter adult content across all household devices. Why Version 21.3.10.391 Still Matters
While newer versions are always being released, version 21.3.10.391 is known for its stability on various Windows builds, including Windows 7 (with SP1), 8.1, and 10. It bridges the gap between legacy support and modern security needs. By combining a VPN, password manager, and top-tier malware protection into one package, it eliminates the need for multiple subscriptions, making it a cost-effective and powerful choice for comprehensive digital defense.
Here is the most likely full file name based on Kaspersky’s naming convention:
Kaspersky Total Security 2021 21.3.10.391 for Windows
Or, as it might appear in an installer file: Kaspersky Total Security 2021 21
kts21.3.10.391en.exe
(where "en" could be replaced by another language code, e.g.,en-US,de,fr,ru)
If you need a full descriptive text for documentation or a download link, here’s an example:
"Kaspersky Total Security 2021 (version 21.3.10.391) for Windows – comprehensive multi-device security including antivirus, VPN, password manager, and parental controls."
If you are installing version 21.3.10.391 on an old machine, these are the requirements:
| 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."
Kaspersky Total Security 2021 (21.3.10.391) was a masterpiece of its time. It balanced heavy protection with a clean UI and offered tools (backup, password manager) that are now sold separately in competitor suites. For a nostalgic user on an old Windows 10 PC, it still functions.
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, upgrade to Kaspersky Plus. If you have a perpetual license, consider using it only on air-gapped or legacy machines.
Final Verdict: Solid for historic preservation or offline use. Not recommended for daily banking or modern gaming.
Have a specific question about this version? Leave a comment below. Disclaimer: Kaspersky Total Security 2021 is classified as end-of-life software. Use at your own risk.
Note: The string appears to be truncated at "W...", which almost certainly stands for Windows.