NotebookLM PPTX Export: What Changed in 2026 and What's Still Broken

The PPTX Export Has Gotten Better — But Not Good Enough

NotebookLM's ability to turn your sources into a slide deck and export it as PPTX is one of its most popular features. Over the past year Google has pushed several improvements: faster generation, more layout variety, and better visual polish. If you used it in early 2025, you'd notice the difference immediately.

But several frustrations remain. The "Made with NotebookLM" watermark still ships on every free-tier export. A surprising number of slides are rasterized images rather than editable text. Font substitution can make your deck look different on every machine. And the formatting, while better, is still inconsistent enough that most users spend time cleaning up the output before presenting.

This article covers what's actually improved, what's still broken, and practical workarounds for each problem — including how to remove the watermark for free.

What's Improved in 2026

Credit where it's due — the PPTX export is meaningfully better than it was a year ago:

• Faster generation — slide decks that used to take 30-60 seconds now typically generate in 10-20 seconds
• More layout templates — Google has added more slide layout options, including title slides, two-column layouts, and image-focused designs
• Better visual consistency — fonts, colors, and spacing are more uniform across slides within a single deck
• Improved source handling — the AI does a better job of pulling key points from your source material and organizing them logically
• Larger source capacity — you can include more source documents, giving the AI more context to work with

For casual use — a quick internal presentation, a study overview, a draft to iterate on — the 2026 PPTX export is genuinely useful. The problems show up when you need something polished enough to present externally.

What's Still Broken

1. The Watermark (Still There, Still Annoying)

Every PPTX exported from the free tier carries a "Made with NotebookLM" watermark. It's not a text box you can select and delete — it's an image layer embedded in each slide's media folder inside the PPTX ZIP structure. You'll find it under ppt/media/ if you unzip the file.

The only official way to remove it is NotebookLM Ultra at $250/month. For a more practical solution, see our step-by-step PPTX watermark removal guide.

2. The Rasterization Problem

This is the biggest quality issue and the least talked about. When NotebookLM generates a PPTX, some slides come out as rasterized images rather than editable objects. Open the file in PowerPoint, click on a slide element, and instead of selecting a text box, you're selecting a single flat image that covers the entire slide.

What this means in practice:

• You can't edit the text — it's baked into a PNG/JPEG image, not a text box
• You can't change fonts or colors — it's pixels, not styled objects
• Scaling looks bad — stretching a rasterized slide makes it blurry
• The file size bloats — each rasterized slide is a full-resolution image (often 2-5MB per slide)

Not every slide gets rasterized. Simple text-heavy slides often export as editable objects. Complex layouts — especially those with custom positioning, overlapping elements, or embedded charts — are more likely to end up as flat images. Google hasn't published clear rules about what triggers rasterization, so it feels random to users.

3. Font Substitution Issues

NotebookLM uses Google Fonts in its slide generation. When you open the PPTX in Microsoft PowerPoint on a system that doesn't have those fonts installed, PowerPoint substitutes them — and the results aren't always pretty:

• Text overflows its containers because the substitute font is wider
• Line breaks shift, creating orphaned words and awkward spacing
• Bold and italic weights may not map correctly
• The deck looks fine on your machine but different on someone else's

Workaround: If you're using PowerPoint on Windows, install the Google Fonts used in the deck (usually Product Sans, Roboto, or Open Sans). On Mac, the issue is less common since macOS includes many overlapping fonts. In Google Slides, the problem doesn't exist because Google Fonts are always available.

4. Formatting Inconsistencies

Even on editable slides, you'll often see:

• Bullet alignment that's slightly off
• Inconsistent spacing between slides (one slide has generous margins, the next is cramped)
• Image placement that overlaps text boundaries
• Color themes that don't quite match between title and content slides

These are cosmetic issues, not deal-breakers. But they add up — if you're spending 20 minutes fixing formatting on a 15-slide deck, the "AI-generated" speed advantage starts to evaporate.

What's Inside a NotebookLM PPTX File

A .pptx file is a ZIP archive containing XML and media files. Understanding this structure helps explain both the watermark problem and the rasterization issue:

presentation.pptx (ZIP)
├── [Content_Types].xml
├── ppt/
│   ├── presentation.xml      ← slide dimensions, theme references
│   ├── slides/
│   │   ├── slide1.xml         ← each slide's content (if editable)
│   │   ├── slide2.xml
│   │   └── ...
│   ├── slideLayouts/          ← layout templates
│   ├── slideMasters/          ← master slide definitions
│   ├── media/
│   │   ├── image1.png         ← rasterized slides live here
│   │   ├── image2.png         ← watermark is embedded in these
│   │   └── ...
│   └── theme/
│       └── theme1.xml         ← color and font definitions
└── docProps/

When a slide is rasterized, the slide*.xml file references a single image from ppt/media/ that fills the entire slide area. When it's editable, the XML contains individual shape elements (<p:sp>) for each text box, image, and graphic.

The watermark sits in the media images. Our PPTX removal tool unpacks the ZIP with JSZip, processes each image in ppt/media/ through the same Canvas-based connected-component detection used for infographic watermarks, removes the badge, and repacks a clean PPTX.

How to Get the Best PPTX Output

You can't fully control what NotebookLM does, but these tips measurably improve results:

Tip	Why It Helps
Keep sources well-structured	Clear headings and bullet points in your source docs produce cleaner slide layouts
Limit slides to 12-15	Shorter decks have fewer rasterized slides and more consistent formatting
Use the prompt to guide structure	"Create a 10-slide presentation with one key point per slide" produces cleaner output than vague requests
Prefer text-heavy over visual-heavy	Slides with primarily text are less likely to get rasterized
Export as PDF first to preview	Check the content before committing to the PPTX — both exports share the same generated slides
Clean the watermark before editing	Remove the watermark first, then make your edits — otherwise the watermark is part of the background you're editing on top of

PPTX vs PDF Export: Which Should You Choose?

Factor	PPTX Export	PDF Export
Editability	Partially editable (some slides rasterized)	Not editable
Watermark removal	Image processing (JSZip + Canvas)	Image processing (pdf.js + Canvas + pdf-lib)
File size	Larger (5-30MB typical)	Smaller (1-10MB typical)
Font issues	Substitution problems on some systems	Fonts embedded, always consistent
Best for	Editing and customizing the deck	Distributing a final, read-only version
Presenting	PowerPoint / Google Slides	Any PDF viewer

Rule of thumb: export as PPTX if you need to edit the slides, export as PDF if you're distributing a finished deck. Either way, remove the watermark before sharing.

Frequently Asked Questions

Why are some of my slides rasterized images instead of editable text?

NotebookLM rasterizes slides with complex layouts — overlapping elements, custom positioning, embedded charts, or unusual formatting. Simple text-heavy slides are more likely to export as editable objects. There's no user-facing setting to control this; it's determined by the AI's rendering pipeline. Keeping your deck shorter and text-focused reduces rasterization.

Can I convert rasterized PPTX slides back to editable text?

Not perfectly. You can use OCR (optical character recognition) to extract text from rasterized slides, but you'll lose formatting, positioning, and styling. For critical presentations, it's often faster to recreate the affected slides manually using the rasterized version as a visual reference. See our PDF to PowerPoint conversion guide for related workflows.

Does removing the watermark affect editable slides?

No. The watermark removal process targets the image files in ppt/media/. Editable XML-based slide content (text boxes, shapes, charts) is not modified. The tool processes the media images — removing the badge from the bottom-right corner — and repacks the same PPTX structure. Your editable content stays exactly as it was.