Topics include Secure Boot certificate update failures, incorrect Secure Boot states, unexpected BitLocker recovery prompts, and boot failures following Secure Boot configuration changes.

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Even when the device has a working Internet connection, a “no Internet” error appears during sign in and prevents access to Microsoft services and apps such as Microsoft Teams. [Remote Desktop] This update improves protection against phishing attacks that use Remote Desktop (.rdp) files.

允许的签名数据库 (DB) 和不允许的签名数据库 (DBX) 确定哪些代码可以在 OS 启动之前在 UEFI 环境中运行。 DB 包括由 Microsoft 和 OEM 管理的证书，而 DBX 由Microsoft使用最新的吊销进行更新。 任何具有 KEK 的实体都可以更新 DB 和 DBX。 Microsoft更新最初在 2011 年颁发的安全启动证书，以确保 Windows 设备继续验证受信任的启动软件。 这些较旧的证书将于 2026 年 6 月开始过期。 未收到较新 2023 证书的设备将继续启动并正常运行，标准 Windows 更新将继续安装。

In this article, we will help you find your error code and suggest what you might try to correct the error. Follow the recommended resolutions for that error code. You may also click the specific error code to get more detail information. Note: This article doesn't contain all error codes generated by Device Manager.

This guide provides detailed steps to troubleshoot and resolve Windows Update problems effectively. If you are using a Windows 11 device, start by running the automated Windows Update troubleshooter in the Get Help app. It will automatically run diagnostics and attempt to fix most of the problems.

To enable the change in behavior and be secure from the vulnerability, you must ensure all Windows domain controllers are updated with a Windows update release on or after April 8, 2025, and the AllowNtAuthPolicyBypass registry key setting is set to 2 to configure for Enforcement mode.

Important: Microsoft Support doesn't have the ability to retrieve, provide, or recreate a lost BitLocker recovery key. A BitLocker recovery key is needed when BitLocker can’t automatically unlock an encrypted drive in Windows. This is a 48‑digit number that lets you regain access to your drive.

To prevent NTLM Relay Attacks on networks with NTLM enabled, domain administrators must ensure that services that permit NTLM authentication make use of protections such as Extended Protection for Authentication (EPA) or signing features such as SMB signing.

These errors typically occur when there is a problem with audio or video codecs. For example, C00D11B1 is a common codec-related error. To resolve this, see how to fix outdated or corrupted codecs. This error may occur when there's an issue with the playback of media files.