Windows 8.1 Update and Windows RT 8.1 Update (also known as KB 2919355) include improvements that make your favorite apps and settings easier to find and use, provide more familiar mouse and keyboard options, and update security and performance.Here’s what you need to know about installing this important update. Check to see if it’s already installed

When you start a focus session, a focus timer will appear on screen. To use additional focus tools in the Clock app, expand the focus timer to get the full view of the Clock app.

There are a few common scenarios in which Windows running on a PC might be discovered to be non-genuine during validation. Repairs. If your PC has been repaired, you might start to see messages on your desktop that Windows isn't genuine.

Find Microsoft Excel help and learning resources. Explore how-to articles, guides, training videos, and tips to efficiently use Excel.

Training: Watch and learn how to use PowerPoint in Windows. Explore PowerPoint training guides, articles, and how-to videos.

Learn more about updates for Windows 10 version 1903, including improvement and fixes, any known issues, and how to get the update.

Important: If your device is out of support, it is no longer receiving security updates from Microsoft and may become more vulnerable to security risks and viruses.For this reason, we strongly recommend that you update to the latest version of Windows. Each version of Windows is supported for 18 months.

若要在Windows 11电脑上使用移动应用，需要安装Amazon Appstore。 设置完成后，你将能够浏览和安装精选目录中的移动应用。

To help protect your privacy, the new Microsoft Edge sets tracking prevention to balanced by default. For increased protection, you can switch your tracking prevention to strict or block all third-party cookies.

IMPORTANT This update is not needed and will not be offered if your Windows Recovery Environment (WinRE) meets any of the following conditions: If the WinRE recovery partition does not have sufficient free space.