Unexpected Pop-up When Saving Word Document as HTML (Microsoft 365 Apps for enterprise - Version 16.0.18526.20264)

Dear Microsoft Support,

I am experiencing an issue when programmatically saving a Word.Document object as HTML using Word automation (Interop) in my application.

Environment details:

• Product: Microsoft 365 Apps for enterprise (en-us)

Version: 16.0.18526.20264

• Operating System: Windows 11 Enterprise, version 23H2 (OS Build 22631.5189)

Problem Description: When I attempt to save a Word document (created or cloned in memory) to HTML format via the SaveAs method, an unexpected pop-up appears during the operation. This dialog interrupts the automated process, which should be fully silent.

I have ensured that:

Application.DisplayAlerts is set to wdAlertsNone before saving.

All tracked revisions are accepted (AcceptAllRevisionsShown()).

All fields are unlinked (Field.Unlink()).

The document is marked as saved (Document.Saved = true) before and after saving.

The document is cleaned to remove problematic characters and objects.

Despite these measures, the pop-up still appears, causing the process to require manual user intervention, which is not acceptable in my automated workflow.

Request: I would appreciate your assistance in:

Understanding why this pop-up appears in the latest Word version during SaveAs(HTML) operation.

Confirming whether this is a known issue, a new behavior introduced recently, or a bug.

Providing guidance or workarounds to ensure a truly silent save to HTML process without any UI interruptions.

Please let me know if you require a minimal reproducible sample or additional logs.

Thank you for your support.

Best regards,

Rotem Rokah