Outlook (classic) stops responding when ItemSend event is executed

[clavx]

Provide required information needed to triage your issue

We have received a number of reports from customers who have applied the latest Current Channel Version 2502, stating that Outlook (classic) stops responding at the end of running our add-in.

Our add-in performs the following operations:

1. Triggers the add-in using the On-send feature (ItemSend event) and displays a dialog using the Office.context.ui.displayDialogAsync method.
2. After the add-in completes its processing, call event.completed({ allowEvent: true }); with the dialog still displayed.

The following is a summary of the information that we have gathered from our customers:

• The issue occurs with the latest Current Channel of Outlook for Windows:
  • Version 2502 (Build 18526.20144)
  • Version 2502 (Build 18526.20168)
• Some users are affected and some are not.
• Disabling the add-in allows Outlook to function normally without freezing.

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: PC desktop
• Host [Excel, Word, PowerPoint, etc.]: Outlook
• Office version number: Version 2502
• Operating System: Windows 11 / Windows 10
• Browser (if using Office on the web): WebView2

Expected behavior

Outlook should work without problems.

Current behavior

The cursor becomes an hourglass and Outlook stops responding.

Steps to reproduce

1. Click the Send button in Outlook
2. The add-in is activated
3. The add-in is processing
4. Outlook has stopped working

It is unclear whether the issue occurs after calling event.completed({ allowEvent: true }); or before. My guess is that it is probably after the call.

Context

We have not been able to reproduce the issue in our testing environment, and we are currently relying solely on customer reports to identify the issue.
We are struggling to respond to this issue as it is not clear whether the issue is caused by a specific process in the add-in or whether other factors are affecting the issue.

For example, have you received any of the following reports?

• Cases in which Outlook, which was working properly, stopped responding after the application of version 2502.
• Related information that suggests that a specific process in the add-in may be causing the issue.

If you have any related information or insights, we would greatly appreciate it if you could share them with us.

Thank you.

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• Outlook on-send Add-In freezing when open a dialog in Desktop #2656

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Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

This issue only exists in Insider Beta version 22061407, it will be fixed in the next Insider Beta release but until that is available you can switch to Current Channel or Current Channel (Preview) which does not have the issue. To switch channels, use Help > Check for Updates > Advance > Update Channel

Reference:

• Outlook on-send Add-In freezing when open a dialog in Desktop #2656 (comment)

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[avisheknand]

Hello, we do have some customers reporting that Outlook (classic) is hanging with OnSend addin, when they click send, it states the addin is working on request and nothing happens. When they restart Outlook, it works fine for sometime and the issue appears again. I believe there has been new updates to Outlook which is causing this issue now.