Hi @Michael Mertens and @Caspar Field,
Thank you for raising your concern and for taking the time to share detailed information about your experience.
From my perspective and based on my observations, this does not appear to be a widespread issue affecting a large number of PowerPoint users. Reports of preserved Slide Masters being removed do exist, but I have not found any official Microsoft documentation confirming this as a known product issue or documented bug. Based on the feedback shared so far, the behavior appears to occur inconsistently and can be difficult to reproduce across different environments.
Your concern is completely valid. Microsoft Q&A is primarily a community-driven support platform. Most contributors here, including moderators, MVPs, independent advisors, and fellow users, do not have a direct connection to the Microsoft product development teams. We do our best to help based on our knowledge and experience, but discussions in the community are not automatically tracked as engineering work items.
That said, there are several ways to provide feedback directly to Microsoft:
- Submit feedback through the Microsoft Feedback Portal.
- Send feedback directly from within the PowerPoint application using Help > Feedback (or the Feedback option available in your Microsoft 365 apps).

- If your organization has access to Microsoft support, consider opening a support case so the issue can be investigated and escalated if necessary.
The Microsoft product team reviews feedback submitted through these channels, and customer reports can help identify patterns, prioritize investigations, and potentially contribute to future improvements or fixes.
I also appreciate @Caspar Field's sharing the challenges you faced when working with multiple Master layouts. I can understand how frustrating it must have been to invest significant time designing and organizing the templates, only to find that PowerPoint was not behaving as expected. Your solution of splitting the content into separate Dark and Light templates, while keeping hidden example slides and explanatory notes, is a practical approach even though it is far from ideal.
Thank all of you again for contributing your findings.