Press and hold (or right-click) the MP4 file you want to play, select Open with, and then choose your preferred file player from the list of applications.

Warning Resetting your console to its factory defaults erases all accounts, saved games, settings, and home Xbox associations. Anything not synchronized with the Xbox network will be lost. Your console syncs with the Xbox network automatically when it’s connected with the service, so if you've been offline for a while, connect to the Xbox service before taking these steps.

Contact Microsoft Support. Find solutions to common problems, or get help from a support agent.

检查你的版本. DirectX 是许多 Windows 游戏都需要的一种多媒体技术套件。 如果你的电脑未安装正确版本的 DirectX（产品包装盒上应标有所需的版本），游戏可能无法正常运行。

Set their account as a standard user: Your child might be set as an Administrator on the device. As an administrator they can change or break the Family Safety settings. Select > Settings > Accounts > Family & other users > Choose your child's account > Change account type > In the dialog choose Standard user and select ok to save the change.

Notes: This feature needs to be turned on by your IT admin. Also, sending email to a channel isn't available if you're using Teams as part of an Office 365 Government plan.. In the case of email attachments, a unique ID is appended at the end of file name to support retry requests for uploading files with same name.

This event is logged when the Secure Boot DBX variable is updated successfully. The DBX variable is used to untrust Secure Boot components and is typically used to block vulnerable or malicious Secure Boot components such as boot managers and certificates used to sign boot managers.

In Teams, the meeting lobby keeps participants from joining a meeting until they’re admitted by an organizer, co-organizer, or presenter. When people are in the lobby, organizers, co-organizers, and presenters are notified and can choose when to admit them to the meeting.

如何兑换礼品卡、Xbox 下载代码或令牌. Microsoft 和 Xbox 礼品卡以及下载代码和令牌的工作方式相同：兑换到 Microsoft 帐户后，可以在 Windows 或 Xbox 上将余额用于Microsoft Store 在线商店，并且可以获取最新应用、游戏、电影、电视节目以及 Surface、Xbox 和配件的下载。

Check the Xbox services, games, and apps for any service outages.