video shows up twice

First determine whether the video appears twice at the same time or instead plays a second time, because these symptoms require different fixes.

If the video plays again after finishing

1. Open the affected slide and select the video.
2. Go to Animations → Animation Pane.
3. Remove any duplicate playback effects, or set the intended effect to On Click or With Previous.
4. Go to Transitions → Advance Slide:
   • Clear After.
   • Select On Mouse Click.
5. Go to Slide Show → Set Up Slide Show:
   • Select Presented by a speaker (full screen).
   • Clear Loop continuously until Esc.
   • Disable recorded timings temporarily and test again.

Timings, looping, and duplicate animation effects can cause a slide or its content to replay during a slide show.^1^

If two copies appear simultaneously

In Normal view:

1. Go to Home → Select → Selection Pane.
2. On the affected slide, hide objects one at a time using the eye icons.
3. If two video objects are listed, delete the unwanted copy.
4. Also inspect the slide’s layout:
   • Select View → Slide Master.
   • Check the layout used by that slide for another video or media placeholder.
   • Close Master View and test the presentation.

If the video is configured to continue across several slides, test after changing it to play only on its original slide. Microsoft currently documents that videos do not play seamlessly across multiple slides after ActiveX controls were disabled by default; the behavior stopped working as expected beginning with Microsoft 365 Version 2505.^2^

For a cross-slide video, the supported workaround for related rendering problems is to insert the video separately on each required slide and trim each copy to the appropriate section.^3^

Because this is an older presentation

Work on a copy first, then select File → Info:

• If Convert or Convert Document appears, use it to upgrade the older presentation/media format.
• If Optimize Compatibility appears, run it and save the presentation under a new name.
• In newer PowerPoint versions, also use File → Info → Check for Issues → Check Compatibility.

PowerPoint can upgrade and embed media inserted by earlier versions. If the video is linked rather than embedded, Optimize Compatibility → View Links → Break Link embeds it, provided the linked file remains accessible.^4^

Finally, install available Office updates through File → Account → Update Options → Update Now, then retest the copied file. Microsoft tracks current PowerPoint for Windows regressions and their status on its known-issues page.^5^

If none of these distinguishes the problem, the useful details for the next diagnosis are:

• Whether the copies are simultaneous or sequential
• Whether Play Across Slides is enabled
• PowerPoint version/build from File → Account → About PowerPoint
• Whether duplication occurs on the laptop screen, an external display, or both

References

1. PowerPoint slides repeating - Microsoft Q&A
2. The “Stop Playing After N Slides” feature is not working as expected in PowerPoint for Windows | Microsoft Support
3. Videos that are set to play across slides display over other shapes during playback in PowerPoint | Microsoft Support
4. Are you having video or audio playback issues? | Microsoft Support
5. Fixes or workarounds for recent issues in PowerPoint for Windows ...