Merge branch 'main' into live

Author: github-actions

docs/excel/excel-add-ins-undo-capabilities.md

@@ -1,7 +1,7 @@
 ---
 title: Undo capabilities with the Excel JavaScript API
 description: Learn how to preserve the undo stack in your Excel add-ins.
-ms.date: 05/15/2025
+ms.date: 06/04/2025
 ms.localizationpriority: medium
 ---
 
@@ -10,7 +10,7 @@ ms.localizationpriority: medium
 Excel add-ins support undo behavior. This preserves both actions performed by Excel JavaScript APIs and actions performed by the user in Excel. These actions are saved in the *undo stack* for an individual user, allowing the user to step back through their actions when desired.
 
 > [!NOTE]
-> The features described in this article are currently available only in public preview. [!INCLUDE [Information about using preview APIs](../includes/using-excel-preview-apis.md)]
+> The features described in this article are currently available only in public preview. [!INCLUDE [Information about using preview APIs](../includes/using-excel-preview-apis.md)] To use this feature, you must also join the [Microsoft 365 Insider Program](https://aka.ms/MSFT365InsiderProgram) and download the latest build of Excel.
 
 ## Undo grouping
 

docs/outlook/autolaunch.md

@@ -1,7 +1,7 @@
 ---
 title: Configure your Outlook add-in for event-based activation
 description: Learn how to configure your Outlook add-in for event-based activation.
-ms.date: 03/11/2025
+ms.date: 06/05/2025
 ms.topic: concept-article
 ms.localizationpriority: medium
 ---
@@ -67,7 +67,7 @@ Because event-based add-ins are deployed by admins, any change you make to the m
 
 ## Event-based activation behavior and limitations
 
-Add-in launch-event handlers are expected to be short-running, lightweight, and as noninvasive as possible. After activation, your add-in will time out within approximately 300 seconds, the maximum length of time allowed for running event-based add-ins. To signal that your add-in has completed processing a launch event, your associated event handler must call the [event.completed](/javascript/api/outlook/office.mailboxevent#outlook-office-mailboxevent-completed-member(1)) method. (Note that code included after the `event.completed` statement isn't guaranteed to run.) Each time an event that your add-in handles is triggered, the add-in is reactivated and runs the associated event handler, and the timeout window is reset. The add-in ends after it times out, or the user closes the compose window or sends the item.
+Event-based add-ins require an internet connection to be able to launch when a specific event occurs. Add-in event handlers are expected to be short-running, lightweight, and as noninvasive as possible. After activation, your add-in will time out within approximately 300 seconds, the maximum length of time allowed for running event-based add-ins. To signal that your add-in has completed processing a launch event, your associated event handler must call the [event.completed](/javascript/api/outlook/office.mailboxevent#outlook-office-mailboxevent-completed-member(1)) method. (Note that code included after the `event.completed` statement isn't guaranteed to run.) Each time an event that your add-in handles is triggered, the add-in is reactivated and runs the associated event handler, and the timeout window is reset. The add-in ends after it times out, or the user closes the compose window or sends the item.
 
 If the user has multiple add-ins that subscribe to the same event, the Outlook platform launches the add-ins in no particular order. Currently, only five event-based add-ins can be actively running.
 

docs/outlook/one-outlook.md

@@ -1,7 +1,7 @@
 ---
 title: Handle OnMessageSend and OnAppointmentSend events in your Outlook add-in with Smart Alerts
 description: Learn about the Smart Alerts implementation and how it handles the OnMessageSend and OnAppointmentSend events in your event-based Outlook add-in.
-ms.date: 05/22/2025
+ms.date: 06/05/2025
 ms.topic: concept-article
 ms.localizationpriority: medium
 ---
@@ -137,7 +137,83 @@ If the **soft block** or **block** option is  used, the user can't send the item
 
 ![Dialog that alerts the user that the add-in process has timed out. The user must attempt to send the item again to activate the add-in before they can send the message or appointment.](../images/outlook-soft-hard-block-timeout.png)
 
-### Outlook client in Work Offline mode
+### Intermittent or no internet connection
+
+Event-based add-ins, including Smart Alerts add-ins, require an internet connection to launch. This section describes how an add-in behaves when Outlook is launched without connectivity, when Outlook experiences intermittent connectivity, and when the Work Offline mode, if applicable to the Outlook client, is turned on.
+
+#### Offline when Outlook launches
+
+When Outlook launches without internet connectivity, it's unable to determine which add-ins are installed. Because of this, Smart Alerts add-ins can't activate when the `OnMessageSend` or `OnAppointmentSend` events occur. In this scenario, to ensure that all mail items are checked for compliance before they're sent, administrators can configure policies in their organization. The policy to be set varies depending on the Outlook client.
+
+# [Web/Windows (new)](#tab/web-new-windows)
+
+For Outlook on the web and new Outlook on Windows, configure the **OnSendAddinsEnabled** mailbox policy in Exchange Online PowerShell.
+
+1. [Connect to Exchange Online PowerShell](/powershell/exchange/connect-to-exchange-online-powershell).
+1. Create a new mailbox policy.
+
+   ```powershell
+    New-OwaMailboxPolicy OWAOnSendAddinAllUserPolicy
+   ```
+
+    > [!NOTE]
+    > Administrators can also use an existing policy.
+
+1. Set the **OnSendAddinsEnabled** flag to `true`.
+
+   ```powershell
+    Get-OwaMailboxPolicy OWAOnSendAddinAllUserPolicy | Set-OwaMailboxPolicy -OnSendAddinsEnabled:$true
+   ```
+
+1. Assign the policy to user mailboxes.
+
+   ```powershell
+    Get-User -Filter {RecipientTypeDetails -eq 'UserMailbox'} | Set-CASMailbox -OwaMailboxPolicy OWAOnSendAddinAllUserPolicy
+   ```
+
+# [Windows (classic)](#tab/windows)
+
+Configure the **Block send when web add-ins can't load** Group Policy setting. When the setting is turned on, mail items are moved to the **Drafts** folder when the **Send** button is selected. This way, when Outlook is able to load add-ins, any installed Smart Alerts add-ins can run checks on the items before they're sent.
+
+To turn on the setting, perform the following:
+
+1. Download the latest [Administrative Templates tool](https://www.microsoft.com/download/details.aspx?id=49030).
+1. Open the **Local Group Policy Editor** (**gpedit.msc**).
+1. Navigate to **User Configuration** > **Administrative Templates** > **Microsoft Outlook 2016** > **Security** > **Trust Center**.
+1. Open the **Block send when web add-ins can't load** setting.
+1. In the dialog that appears, select **Enabled**.
+1. Select **OK** or **Apply** to save your change.
+
+# [Mac](#tab/mac)
+
+For Outlook on Mac, the **OnSendAddinsWaitForLoad** mailbox key must be configured on each user's machine. This key ensures that add-ins are loaded from Exchange and are available to run checks on outgoing items. As the **OnSendAddinsWaitForLoad** key is CFPreference-compatible, it can be set by any enterprise management software for Mac, such as Jamf Pro. The following table provides details about the key.
+
+|Field|Value|
+|:---|:---|
+|**Domain**|com.microsoft.outlook|
+|**Key**|OnSendAddinsWaitForLoad|
+|**DataType**|Boolean|
+|**Possible values**|`false` (default): The currently downloaded manifests of the Smart Alerts add-ins (not necessarily the latest versions) run on outgoing mail items.<br><br>`true`: After the latest manifests of the Smart Alerts add-ins are downloaded from Exchange, the add-ins run on outgoing mail items. Otherwise, the item is blocked from being sent and the **Send** button becomes unavailable.|
+|**Availability**|16.27|
+|**Comments**|This key creates a policy to ensure that outgoing mail items are checked for compliance before they're sent.|
+
+---
+
+#### Intermittent connection
+
+> [!NOTE]
+> In classic Outlook on Windows and on Mac, the behavior of a Smart Alerts add-in is different while in [Work Offline mode](https://support.microsoft.com/office/f3a1251c-6dd5-4208-aef9-7c8c9522d633). For more information, see [Outlook client in Work Offline mode](#outlook-client-in-work-offline-mode).
+
+If Outlook was able to load any Smart Alerts add-ins that are installed, but loses connection when an `OnMessageSend` or `OnAppointmentSend` event occurs, the behavior differs depending on the send mode option implemented by the add-in.
+
+If the **prompt user** or **soft block** option is used, the following behavior applies.
+
+- **Send Anyway** option is selected: The mail item is moved to the **Outbox** folder. When a connection is reestablished, the item is automatically sent.
+- **Don't Send** option is selected: The mail item is saved to the **Drafts** folder. This prevents the item from being automatically sent when a connection is reestablished. When Outlook is back online and the user selects **Send**, the Smart Alerts add-in is activated.
+
+If the **block** option is used, the mail item is saved to the **Drafts** folder and a dialog is shown to the user notifying them to reconnect. This prevents the item from being automatically sent when a connection is reestablished. When Outlook is back online and the user selects **Send**, the Smart Alerts add-in is activated.
+
+#### Outlook client in Work Offline mode
 
 In Outlook on Windows (classic client starting in Version 2310 (Build 16913.10000)) and on Mac (starting in Version 16.80 (23121017)), a Smart Alerts add-in that implements the **soft block** or **block** option can only process a mail item while the Outlook client is online. If [Work Offline mode](https://support.microsoft.com/office/f3a1251c-6dd5-4208-aef9-7c8c9522d633) is turned on in the Outlook client when a mail item is sent, the item isn't saved to the **Outbox** folder and the user is alerted that they must deactivate Work Offline mode before they can attempt to send their item.
 
@@ -149,7 +225,7 @@ If the Smart Alerts add-in implements the **prompt user** option, it doesn't pro
 
 When a user navigates away from the message they're sending (for example, to read a message in their inbox), the behavior of a Smart Alerts add-in differs between Outlook clients. Select the tab for the Outlook client on which the add-in is running.
 
-# [Web/New Outlook on Windows](#tab/web)
+# [Web/Windows (new)](#tab/web-new-windows)
 
 In Outlook on the web or in [new Outlook on Windows](https://support.microsoft.com/office/656bb8d9-5a60-49b2-a98b-ba7822bc7627), a user must remain on the message being sent until the Smart Alerts add-in completes processing it. Otherwise, once the user navigates away from the item, the add-in terminates the Smart Alerts operation and saves a draft to the mailbox's **Drafts** folder. The user is then alerted that they must resend the message from the **Drafts** folder and remain on the message until the add-in completes processing it.
 

docs/outlook/onmessagesend-onappointmentsend-events.md

@@ -1,19 +1,20 @@
 ---
 title: Outlook add-ins overview
 description: Outlook add-ins extend or customize the Outlook UI and are developed by Microsoft and partners using our web-based platform.
-ms.date: 02/19/2025
+ms.date: 06/05/2025
 ms.topic: overview
 ms.custom: scenarios:getting-started
 ms.localizationpriority: high
 ---
 
 # Outlook add-ins overview
 
-Outlook add-ins are solutions that extend the functionality of the Outlook client through a web-based platform. Outlook add-ins have three key aspects.
+Outlook add-ins are solutions that extend the functionality of the Outlook client through a web-based platform. Outlook add-ins have the following key aspects.
 
-- The same add-in and business logic works across web (Microsoft 365 and Outlook.com), desktop (Outlook on Windows (classic) and on Mac), and mobile.
-- Outlook add-ins consist of a manifest, which describes how the add-in integrates into Outlook (for example, a button or a task pane), and JavaScript/HTML code, which makes up the UI and business logic of the add-in.
-- Outlook add-ins can be acquired from [AppSource](https://appsource.microsoft.com) or [sideloaded](sideload-outlook-add-ins-for-testing.md) by end-users or administrators.
+- The same add-in and business logic works across web (Microsoft 365 and Outlook.com), desktop (Outlook on Windows ([new](https://support.microsoft.com/office/656bb8d9-5a60-49b2-a98b-ba7822bc7627) and classic) and on Mac), and mobile.
+- Outlook add-ins consist of a manifest, which describes how the add-in integrates into Outlook (for example, a button, task pane, or event). It also includes JavaScript and HTML code, which make up the UI and business logic of the add-in.
+- Outlook add-ins can be acquired from [AppSource](https://appsource.microsoft.com) or [sideloaded](sideload-outlook-add-ins-for-testing.md) by end users or administrators.
+- Outlook add-ins require a network connection to run.
 
 Outlook add-ins are different from COM or VSTO add-ins, which are older integrations specific to Outlook running on Windows. Unlike COM add-ins, Outlook add-ins don't have any code physically installed on the user's device or Outlook client. For an Outlook add-in, Outlook reads the manifest and hooks up the specified controls in the UI, and then loads the JavaScript and HTML. The web components all run in the context of a browser or webview control in a sandbox.
 
@@ -89,7 +90,7 @@ However, add-ins won't activate on IRM-protected items when:
 
 ## Supported clients
 
-Outlook add-ins are supported in Outlook on the web, Outlook on Windows ([new](https://support.microsoft.com/office/656bb8d9-5a60-49b2-a98b-ba7822bc7627) and classic), Outlook on Mac, Outlook on iOS, Outlook on Android, and Outlook.com. Not all of the newest features are supported in all clients at the same time. For details about feature support on clients and servers, see [Requirement sets supported by Exchange servers and Outlook clients](/javascript/api/requirement-sets/outlook/outlook-api-requirement-sets#requirement-sets-supported-by-exchange-servers-and-outlook-clients) and articles specific to those features.
+Outlook add-ins are supported in Outlook on the web, Outlook on Windows (new and classic), Outlook on Mac, Outlook on iOS, Outlook on Android, and Outlook.com. Not all of the newest features are supported in all clients at the same time. For details about feature support on clients and servers, see [Requirement sets supported by Exchange servers and Outlook clients](/javascript/api/requirement-sets/outlook/outlook-api-requirement-sets#requirement-sets-supported-by-exchange-servers-and-outlook-clients) and articles specific to those features.
 
 ## Get started building Outlook add-ins