April 9, 2025—KB5055547 (OS Build 10240.20979)
Applies To
Windows 10Release Date:
4/8/2025
Version:
OS Build 10240.20979
Support for Windows 10 will end in October 2025
After October 14, 2025, Microsoft will no longer provide free software updates from Windows Update, technical assistance, or security fixes for Windows 10. Your PC will still work, but we recommend moving to Windows 11.
For information about Windows update terminology, see the article about the types of Windows updates and the monthly quality update types. For an overview of Windows 10, version 1507, see its update history page.
Important Windows updates do not install Microsoft Store application updates. If you are an enterprise user, see Microsoft Store apps - Configuration Manager. If you are a consumer user, see Get updates for apps and games in Microsoft Store.
Summary
This cumulative update for Windows 10, version 1507 contains security and quality improvements. The following is a summary of the key issues that this update addresses. The bold text within the brackets indicates the item or area of the change we are documenting.
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This update addresses security issues for your Windows operating system.
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[Daylight Saving Time (DST)] Update for the Aysen region in Chile to support the government DST change order in 2025. For more information about DST changes, see the Daylight Saving Time & Time Zone Blog.
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[OS Security] After installing this update or a later Windows update, a new %systemdrive%\inetpub folder will be created on your device. This folder should not be deleted regardless of whether Internet Information Services (IIS) is enabled on the target device. This behavior is part of changes that increase protection and does not require any action from IT admins and end users. For more information, see CVE-2025-21204.
If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device.
For more information about security vulnerabilities, please refer to the new Security Update Guide website and the April 2025 Security Updates.
Known issues in this update
Microsoft is not currently aware of any issues with this update.
How to get this update
Before you install this update
To install any Windows 10, version 1507 cumulative update released on or after January 14, 2025, you must first install the latest Servicing Stack Update (SSU). If your device or offline image does not have the latest SSU installed, you cannot install this update.
Caution Until you install the SSU, this update will not be offered to your device. To reduce your security risk, install the SSU as soon as possible.
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If you use Windows Update, the latest SSU (KB5055664) will be offered to you automatically. After the latest SSU is installed, you will be able to install this update.
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If you use Windows Update for Business, the latest SSU (KB5055664) will be offered to you automatically. After the latest SSU is installed, you will be able to install this update.
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If you use the Update Catalog, you must download and install the latest SSU (KB5055664). After the latest SSU is installed, you will be able to install this update.
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If you are a Windows Server Update Services (WSUS) administrator, you must approve SSU KB5055664 and this update KB5055547.
For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
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This update will be downloaded and installed automatically from Windows Update and Microsoft Update. |
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This update will be downloaded and installed automatically from Windows Update for Business in accordance with configured policies. |
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To get the standalone package for this update, go to the Microsoft Update Catalog website. |
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This update will automatically sync with Windows Server Update Services (WSUS) if you configure Products and Classifications as follows: Product: Windows 10 Classification: Security Updates |
File information
A list of the files that are included in this update are provided in a CSV (Comma delimited) (*.csv) file. The file can be opened in a text editor such as Notepad or in Microsoft Excel.
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