What is Out-of-band (OOB) in Windows Updates?

Out-of-band (OOB) is a term that in the Microsoft ecosystem is often associated with urgent updates released outside the normal schedule., but it also appears in other technical contexts (remote network management, package distribution in .NET, and socket communication). If you've seen references to OOB and gotten confused, you're not alone.: The meaning changes depending on the area and it is important to separate them clearly.

In the realm of Windows Update, an OOB update is a one-off patch that Microsoft releases to fix critical bugs or recent regressions., without waiting for the usual “patch Tuesday”. In recent years we have seen OOB to solve problems with VPN, domain controllers, SSL/TLS handshake, errors when resetting the computer, and other serious failures. At the same time, in .NET, we talk about “out-of-band versions” for libraries distributed via NuGet, in networking, there is “Out-of-Band Management” (OOBM), and in TCP sockets, “out-of-band data” describes an urgent channel parallel to the normal flow.

What does Out-of-band mean in Windows Updates?

An OOB update in Windows is a patch that is released exceptionally to address issues that cannot wait. to the next monthly wave. Microsoft uses them when there are issues affecting connectivity, stability, security, or the ability to system recovery, and their priority is to return things to normal as soon as possible.

The distribution of these OOB varies: Sometimes they appear as an optional update in Windows Update, and other times are published in the Microsoft Update Catalog for manual download. There can also be both standalone and cumulative packages., so that a single installer includes previous fixes along with the new solution.

For home users, it is usually enough to have Windows Update activated and force the search for updates.. In professional environments it is advisable to first validate in a pilot group, especially when the OOB is not security-related and there are sensitive business dependencies. Microsoft documents changes and known side effects, so checking the Windows Message Center and release notes is key.

In specific cases, Microsoft has recognized side effects after installing an OOB (for example, occasional audio issues or unexpected behavior in certain applications), and recommends reporting them through Feedback Hub and following official noticesThe balance lies in quickly solving the critical problem without introducing others, which sometimes requires iterating with additional patches.

Real-life cases: Out-of-Home (OOB) solutions for critical Windows issues

A notable example occurred on January 17, 2022., when Microsoft launched Out-of-box updates to address VPN connectivity issues, unexpected restarts in Windows Server domain controllers, errors of Boot en Virtual machines y mounting ReFS mediaThese fixes were released as optional updates on Windows Update for multiple versions:

• Windows 11, version 21H1 (original release): KB5010795
• Windows Server 2022: KB5010796
• Windows 10, version 21H2: KB5010793
• Windows 10, version 21H1: KB5010793
• Windows 10, version 20H2; Windows Server, version 20H2: KB5010793
• Windows 10, version 20H1; Windows Server, version 20H1: KB5010793
• Windows 10, version 1909; Windows Server, version 1909: KB5010792
• Windows 10, version 1607; Windows Server 2016: KB5010790
• Windows 10, version 1507: KB5010789
• Windows 7 SP1: KB5010798
• Windows Server 2008 SP2: KB5010799
• Windows 8.1? Windows Server 2012 R2: KB5010794
• Windows Server 2012: KB5010797

That batch responded to incidents that had a direct impact on operational continuity., especially in corporate networks. The recommendation was to update the affected equipment as soon as possible. and verify that automatic updates were enabled where applicable.

Another notable episode was an OOB to fix handshake flaws in SSL/TLS after the October 2022 patches, which could cause errors SEC_E_ILLEGAL_MESSAGE on clients and servers. Microsoft explained that some connections could receive one or more records in a single buffer followed by a partial record of less than 5 bytes, triggering the problem in certain batteries and applications.

Affected versions included multiple editions of Windows 11 and Windows 10., with packages such as KB5018427, KB5018418, KB5020387, KB5020435 and others, plus KBs for Windows 8.1 and Windows 7 SP1. Some of those OOBs were obtained through Windows Update automatically.While Others required manual download from the Microsoft Update CatalogIt was reported that Some devices may experience audio issues after installing the fix, an effect that Microsoft continued to investigate.

Out-of-box update for recovery errors in August 2025

In August 2025, Microsoft acknowledged high-impact failures when attempting to reset computers after installing the monthly security updates. PC reset could fail and, in some cases, compromise system data recovery., affecting users and professionals who use RemoteWipe in managed deployments.

The company released a non-security cumulative OOB update to fix the issue. Introduced by the August 2025 update (KB5063874). It was indicated that it also incorporated improvements from KB5063874 itself., avoiding having to apply previous updates before installing it.

Versions indicated in the reports of damage included Windows 10 22H2, Windows Enterprise LTSC 2021, Windows 10 IoT Enterprise LTSC 2021 (KB5063709), Windows 11 22H2 and 23H2 (KB5063875) and Windows 10 Enterprise LTSC 2019; Windows 10 IoT Enterprise LTSC 2019 (KB5063877). Windows 11 24H2 was the great exception, as it is not affected by this specific failure.

There have also been reports of potential issues with large file transfers. SSD linked to KB5063878, although It was not officially confirmed whether a specific solution was being worked on. for that behavior. In any case, The general recommendation was to apply corrective OOB and monitor official Microsoft communications for any additional patches.

Best practices when applying OOB updates

If you are a home user, make sure Windows Update is active and perform a manual check for updates. when Microsoft releases an OOB. In many cases they are installed automatically or appear as “optional”, depending on the nature of the patch and the version of Windows.

In organizations, test first in controlled rings and document changes. Some OOBs are only in the Microsoft Update Catalog and require manual installation or through your management tools. Check for known side effects and Windows health status on the official message board. to adjust your maintenance window. Useful reference: Windows Message Center.

When an OOB targets networks, domain controllers, or encryption, implies a high operational risk if not corrected soon. Weighs the impact of continuing with the incidence against the risk of introducing a minor regression when updating. In general, out-of-the-box patches respond to emergencies that warrant rapid deployment.

If something goes wrong after installation (audio, apps concrete, etc.), Log the issue on Feedback Hub and see workarounds that Microsoft may propose while a further review is pending. Keep backups and restore points if your IT policy allows it.

Other uses of the term OOB that may confuse you

The acronym OOB does not always refer to Windows Update.. In Microsoft documentation and technical jargon it also appears under .NET, networks and communicationsIt is important to distinguish them so as not to mix up concepts or procedures.

Out-of-band (OOB) in .NET: Out-of-band packages and features

In the .NET Framework, “out of band” identifies components and functionality that Microsoft releases outside of the platform's own lifecycle.. The goal is to accelerate the delivery of cross-platform enhancements or introduce capabilities without waiting for a major release. of the Framework.

These OOB packages are distributed via NuGet, the package manager for .NET integrated into Visual Studio since 2012. The big advantage is that the application can include those assemblies with its own installer., without requiring the user to have the latest full version of the .NET Framework installed on the system.

How do I add them from Visual Studio? It's simple: Open the project context menu and choose “Manage NuGet Packages”; in the left panel select “Online”, Activate preview versions if you need to, and search for the desired package. Many official Microsoft packages are recognized by the .NET logo and the Microsoft editor.When you compile and deploy, OOB assemblies travel with your application.

Types of versions: : it is usual for an OOB package to go through preliminary versions (usually non-redistributable, testing and feedback oriented) and a stable version licensed for redistribution. Microsoft provides support, IntelliSense and documentation for stable packages, and in some cases publish the source codeTo stay up-to-date, their technical blog announces new or updated packages.

Out-of-Band Management (OOBM) in networks

Out-of-Band Management is a secure, alternative method for accessing network computers and devices without relying on the corporate LAN.. It is vital when the main network fails or when you need to intervene remotely as if you were connected locally..

Software tools are used to monitor and resolve problems remotely., But depend on the network being operational. A console server provides OOBM access based on hardware, with ports USB, RS-232 or Ethernet, for Reconfigure, reboot, or reimagine devices from anywhere and on any platform, minimizing There of inactivity.

If you combine these servers with a centralized management platform in the cloud or on-prem, you get a Single pane of glass for secure access, scalable deployment, configuration editing, firmware updates, monitoring, and automation. It is an especially useful approach in large distributed companies (banking, insurance, hospitals, utilities, retail or education) without on-site IT staff.

In a NOC, the best platforms allow automate scheduled maintenance, inventory equipment and analyze performance, collect statistics and generate reports from data in SQL, run scripts to deployments, firmware verification, and configuration distribution, and reduce manual intervention so that everything runs smoothly.

OOB data on sockets and TCP: urgent out-of-sequence channel

In the abstraction of stream sockets there is the notion of “out-of-band data”: A independent logical channel associated with a pair of connected sockets allowing mark and deliver special data outside the normal flow. Protocols like TCP implement it as “urgent” data.

In Windows Sockets you can check if there is pending OOB data with ioctlsocket/WSAIoctl and SIOCATMARK, and decide how to read them. If you do not activate SO_OOBINLINE, the application receives FD_OOB notifications (by WSAAsyncSelect) or the socket appears in exceptfds when using select, and You can read the urgent block with MSG_OOB without mixing with the normal flow.

If you enable SO_OOBINLINE, urgent data is integrated in the correct order of the flow.. You cannot use MSG_OOB in that case, and the notifications arrive as if they were normal data (FD_READ/readfds). Urgent block limits are respected, so the readings clearly separate what is before, what is urgent, and what is after.

In TCP there are historical nuances between BSD semantics and what is required by RFC 1122: In BSD the urgent pointer points to the byte after the urgent, while in RFC 1122 it points to the urgent byte itself. This can cause problematic interoperability. if one end assumes one model and the other the opposite. Therefore, It is not recommended to use OOB data unless absolutely necessary. to talk to an existing service, and it is recommended that Providers document their semantics.

How to distinguish each type of OOB according to your needs

If your problem is a serious issue after a Windows patch (VPN, SSL/TLS, PC reset), you are facing Windows Update out-of-the-box updates. Find the corresponding KB in Windows Update or in the Microsoft Update Catalog and apply the patch according to your policy.

If you are a .NET developer and need an API or enhancement that is not in the base Framework, we talk about OOB packages via NuGet. Add them to your project and distribute the assemblies with your application without requiring the latest Framework from the user.

If you manage infrastructure and need access when the LAN is down, yours is OOBM: Console servers and a centralized platform to ensure access, visibility, and automation without relying on the main network.

If you debug communications or develop at low level with sockets, OOB implies urgent data out of the flow with options like SO_OOBINLINE, brands like FD_OOB, and calls like recv with MSG_OOB. Adjust behavior based on your protocol and interoperability needs.

The term OOB groups together different concepts that should not be mixed up.: Windows Update hotfixes, .NET packages distributed via NuGet, out-of-band remote management, and time-sensitive data over sockets. Understanding the context will allow you to act quickly on critical incidents, choose the right deployment strategy, and avoid technical confusion. when you read “Out-of-band” in documentation or release notes.