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MC694387 Outlook on the web: Replacing “Activity-Based Authentication Timeout” with “Idle Session Timeout for Microsoft 365” 要約

  • 2024年2月6日



「Outlook on the webのアクティビティ ベース認証タイムアウト」は、「Microsoft 365 のアイドル セッション タイムアウト」に置き換えられます。


そもそもMicrosoft 365 のアイドル セッション タイムアウト自体は2022年には公開されていた機能で、テナントに対して設定可能で、一定時間M365上で操作がされていなかった後に再操作しようとするとログイン情報の再入力を求めるという機能です。Outlook for the webだけでなく、様々なOffice製品だったりM365上のアプリに対しても設定可能です。

「Outlook on the webのアクティビティ ベース認証タイムアウト」はその名前の通り、Outlook on the webだけでしか動作しないので、単純に「Microsoft 365 のアイドル セッション タイムアウト」が上位互換となるので移行せよ、というのが今回の趣旨となります。

大事なこととしては、自動移行しないので、Outlook on the webに対しては手動で設定しておく必要があります。


Starting in the second half of 2024.

second half of the year で下半期という意味です。対義語はthe first half of yearです。





Updated February 2, 2024: We have updated the content below with additional information. Thank you for your patience.

The Activity-Based Authentication Timeout for Outlook on the web will be replaced by Idle Session Timeout for Microsoft 365.

When this will happen

Starting in the second half of 2024.

How this affects your organization

In January 2024, we will begin to end support for Activity-Based Authentication Timeout. It is strongly recommended that all organizations who have not migrated to Idle-Session Timeout and are still using Activity-Based Authentication Timeout migrate to Idle Session Timeout, since no organization will be migrated automatically

Idle Session Timeout is already available and provides the same functionality as Activity-Based Authentication Timeout with the benefit of allowing the configuration not only for Outlook on the web, but for a range of other Microsoft 365 web apps.

To check the list of Microsoft 365 web apps, click Details about idle session timeout.

What you can do to prepare

You can migrate to Idle Session Timeout right now. To migrate to Idle Session Timeout, you only need to turn on Idle Session Timeout.

When Idle Session Timeout is enabled, users that reach the configured idle session timeout duration will get a notification that they are about to be signed out. They have to select to stay signed in or they will be automatically signed out of Microsoft 365 web apps, including Outlook on the web.

For more information about how to turn on Idle Session Timeout, click Turn on Idle session timeout.

For more information about Idle Session Timeout for Microsoft 365, click Idle session timeout for Microsoft 365.

For more information about Activity-Based Timeout for Microsoft Outlook on the web, click Description of the Activity-Based Authentication Timeout for OWA in Office 365.