This article provides a detailed breakdown of the components managed by the two primary update engines on your Windows device: Windows Update and Click-to-Run.
1. Windows Update
2. Click-to-Run (C2R)
Windows Update
Windows Update is the core service integrated into the Windows operating system. It is primarily responsible for the stability, security, and hardware compatibility of your machine.
Core Operating System Updates
Security Patches: Critical fixes for vulnerabilities within the Windows kernel and system services. These protect your device from malware and exploits.
Quality and Cumulative Updates: Monthly bundles of non-security fixes that improve system reliability and performance.
Feature Updates: Major version upgrades for the Windows OS (e.g., transitioning from Windows 11 23H2 to 24H2) that introduce new system-wide capabilities.
Hardware and Firmware
Device Drivers: Updates for integrated and peripheral hardware, including graphics cards (GPU), network adapters (Wi-Fi/Ethernet), audio controllers, and printers.
System BIOS/UEFI: Firmware updates delivered by hardware manufacturers to improve motherboard stability and power management.
Security Definitions
Microsoft Defender Antivirus: Daily (or more frequent) security intelligence updates that provide the latest definitions to recognize new viruses and threats.
Malicious Software Removal Tool (MSRT): A utility that runs in the background monthly to remove specific, high-prevalence malware from the system.
Extended Microsoft Products (Optional)
If the "Receive updates for other Microsoft products" setting is enabled, Windows Update also manages:
Legacy Office: MSI-based versions of Office 2013 and 2016.
.NET Framework: Core programming libraries used by various Windows applications.
Server Products: Updates for SQL Server and other enterprise-grade Microsoft tools installed on the device.
The following is a list of other Microsoft products that might be updated:
- Active Directory Rights Management Service
- AppFabric
- Azure Connected Machine agent
- Azure File Sync
- Bing Bar
- Bing IME
- BizTalk
- East Asia IME for Windows Content
- Exchange
- IME Dictionary Update
- Live Search
- MED-V
- Microsoft Advanced Threat Analytics
- Microsoft Application Virtualization
- Microsoft Azure StorSimple
- Microsoft Configuration Manager
- Microsoft Dynamics CRM
- Microsoft Information Protection
- Microsoft Lync Server and Microsoft Lync
- Microsoft Monitoring Agent
- Microsoft SRS Device
- Microsoft StreamInsight
- Mobile and IoT
- MSRC
- .NET (also known as .NET Core)
- Office 2016 (MSI versions of Office)
- PlayReady
- Security intelligence updates for Microsoft Defender Antivirus and other Microsoft antimalware
- Silverlight
- Skype for Business
- SQL Server 2014
- SQL Server 2016
- SQL Server 2025
- System Center Application Controller
- System Center Data Protection Manager
- System Center Operations Manager
- System Center Orchestrator
- System Center Virtual Machine Manager
- Visual Studio
- Windows Admin Center
- Windows Azure Hyper-V Recovery Manager
- Windows Azure Pack - Web Sites
- Windows Azure Pack
- Windows Azure Service Bus
- Windows Embedded Developer Update
- Windows Live Sign-in Assistant
- Windows Small Business Server
- Zune
Click-to-Run (C2R)
Click-to-Run is a streaming and virtualization technology used to install and update modern Microsoft 365 and Office products. It operates independently of the Windows Update schedule.
Microsoft 365 Subscription Suites
All applications included in the Microsoft 365 ecosystem are updated via C2R. This ensures that users always have the latest features and security improvements without waiting for a full OS update cycle.
Core Productivity Apps: Word, Excel, PowerPoint, and Outlook.
Specialized Apps: Access, Publisher, and OneNote.
Perpetual Desktop Versions
Starting with Office 2019, Microsoft transitioned all one-time purchase versions of the suite to the Click-to-Run model.
Office Versions: Office 2019, Office 2021, and Office 2024.
Editions: Home & Student, Home & Business, and Professional.
Standalone Professional Tools
Even when purchased as individual applications outside of a suite, the following products utilize Click-to-Run for delivery and maintenance:
Microsoft Project: Standard and Professional editions (2016 and newer).
Microsoft Visio: Standard and Professional editions (2016 and newer).
Shared Components and Proofing Tools
Office Language Packs: Updates to user interface languages and proofing tools (spellcheck, grammar) for all supported languages.
Access Runtime: The runtime environment used to execute Access database files on machines without the full version of Access installed.
Skype for Business: The version of the client specifically bundled with Microsoft 365 Apps.