If a PowerPoint (.pptx) presentation you uploaded shows blank slides, fails to upload, or displays fonts and images incorrectly, it's almost always related to how the file was built or exported — not a bug in the file itself. This article explains the most common causes and how to avoid them.
Why This Happens
Our platform renders PPTX files using a browser-based viewer, which is fast and lightweight but has stricter limits than PowerPoint itself. A handful of issues account for most of the reports we see:
1. Unsupported "Transform" (Morph) transition
The Transform/Morph slide transition is not supported by the viewer. Slides using it render as a blank screen instead of the intended animation.
2. Blocked slides
Slides that are marked as blocked/restricted don't render in their original position in the deck. Instead, they appear as blank slides at the end of the presentation.
3. Oversized images and large SVGs
Very large images — and especially large or complex SVG files — increase processing load. Big SVGs in particular can break the upload entirely, not just slow it down.
4. Custom fonts not embedded or not registered on the platform
If a presentation uses custom (non-standard) fonts and those fonts aren't embedded in the file, the viewer falls back to a default font. Even when embedded, the platform itself also needs the font added on its side to display it correctly.
5. Files built with third-party tools instead of PowerPoint
Presentations created and exported directly from Microsoft PowerPoint are fully supported. Files built in third-party tools (for example, Canva or AI-based presentation generators) and then exported as .pptx can produce unexpected rendering issues, since these tools don't always structure the file the same way PowerPoint does.
Best Practices Before Uploading
- Don't use the Transform/Morph transition. Use a supported transition (e.g., Fade, Push) instead — Transform will show as a blank screen.
- Avoid oversized images. Resize and compress images before adding them to a slide rather than relying on PowerPoint to scale down a huge original file.
- Avoid large or complex SVG images. They can break the upload. If you need vector graphics, keep the SVG simple, or convert it to a PNG/JPEG.
- Check for blocked slides before uploading. A blocked slide won't render where it belongs — it will show up as a blank slide at the end of the deck instead. Unblock, remove, or replace any restricted slides first.
- Internal links work fine within a single file. Links that jump to another slide in the same presentation work as expected, as long as everything stays in one .pptx file. Don't rely on links pointing to slides in a separate file.
- Embed custom fonts, and notify your CSM in advance. If the deck uses custom fonts, embed them in the file (PowerPoint: File > Options > Save > "Embed fonts in the file"). You'll also need to request your CSM to add those fonts to the platform beforehand — embedding alone isn't enough if the platform doesn't already support the font.
- Keep the file size under 100MB.
- Keep the deck to 100 slides or fewer. If your presentation is longer, split it into multiple files.
- Prefer building and exporting your deck directly in Microsoft PowerPoint. Files created in third-party tools (e.g., Canva, AI presentation generators) and exported as .pptx are more likely to show unexpected rendering issues.
If a Presentation Is Already Showing Issues
- Confirm it's a rendering issue, not a corrupted file. The presentation usually opens and plays fine in PowerPoint itself — this confirms the file is structurally valid.
- Check for the Transform transition and blocked slides first, since these are the most common causes of unexpected blank slides.
- Re-export or rebuild the file using the guidelines above: remove/replace the Transform transition, resize large images, simplify or convert large SVGs, and embed any custom fonts.
- If the problem persists, share the file with support so we can inspect the underlying slide structure directly.
Quick Reference
| Symptom | Likely Cause | Fix |
|---|---|---|
| A slide (or the transition into it) shows a blank screen | Transform/Morph transition used | Replace with a supported transition (e.g., Fade) |
| One or more blank slides appear at the end of the deck | Slide(s) marked as blocked/restricted | Unblock, remove, or replace the affected slide(s) |
| Links between slides don't work | Links point to slides in a different file | Keep all linked slides within the same .pptx file |
| Fonts look wrong or fall back to a default | Custom font not embedded, or not added to the platform | Embed the font in the file AND ask your CSM to add it to the platform |
| File won't upload | Large/complex SVG image, or file exceeds 100MB | Simplify/convert the SVG, compress images, or split the file |
| Upload fails or times out on a very large deck | Too many slides in one file | Split into multiple files of 100 slides or fewer |
| General/unpredictable rendering issues | File built with a third-party tool (e.g., Canva, AI generator) rather than PowerPoint | Rebuild or export the deck directly from Microsoft PowerPoint |
Still stuck? Reach out to support with the affected file attached, and we'll take a closer look.