NotebookLM limitations and common pitfalls, and how to avoid them

NotebookLM, now called Gemini Notebook, only answers from the sources you add, can't search across notebooks, caps each source at 500,000 words or 200 MB, imports only the text of web pages and YouTube transcripts, and limits how much you can ask every few hours. Most bad results come from a few habits: trusting citations without checking, one giant notebook, and assuming charts or scanned pages came through. Here's each limit and how to work around it.

This guide lists the hard limits Google states, the pitfalls that cause wrong or weak answers, how to remove sources, and when to use something else. Facts come from Google's Gemini Notebook help pages, checked on 19 October 2026, plus our own tests in a notebook with made-up files.

The hard limits

12 common pitfalls, and how to avoid them

1. Expecting answers your files don't contain. Google says chat answers "only use data from your sources." If your sources don't cover it, add a source or ask a general assistant.
2. Trusting citations without opening them. Google's own warning: "Gemini Notebook can make mistakes," so "be sure to double check it." In our test with pasted text, hovering a citation showed the top of the source rather than the exact line, so click through and find the sentence yourself.
3. One giant notebook, or too many small ones. Notebooks can't see each other, so splitting by topic breaks questions that compare topics. Keep things you'll compare in the same notebook.
4. Assuming a link brought in the whole page. Only the text comes in. Charts and images on the page are dropped, and paywalled articles fail.
5. Adding videos without captions. No captions, no transcript, no source.
6. Assuming charts, tables and scans came through. Google says "certain types of images may not work as well" and doesn't say how it handles charts or scanned pages. Ask a question about a chart before you rely on it, and run scans through OCR first.
7. Editing a file and expecting the notebook to update. Only Google Drive sources sync, every few minutes. Uploaded files and pasted text are copies, so re-upload after changes.
8. Copying a notebook to share it. "Chat history & notes are not copied." Share the original instead, or export what matters first.
9. Editing exports and expecting them to sync. Notes exported to Google Docs or Sheets don't sync back.
10. Sharing too widely. Personal accounts can share with up to 50 people and can't share with Google Groups. Viewers may still see sources and outputs, even in chat-only mode.
11. Doing note work on your phone. The mobile app can't edit notes, and can't generate notes, mind maps, reports or data tables yet.
12. Uploading confidential files without thinking. On personal accounts, Google says content isn't used to directly train its models unless you send feedback, but feedback can be read by human reviewers and kept up to three years. Google also says not to rely on it for "medical, legal, financial, or other professional advice."

How to remove a source

1. Open the notebook and find the source in the Sources panel on the left.
2. Hover over the source and click the three dots that appear.
3. Choose Remove source, then confirm.

We found no built-in way to remove several sources at once; they go one by one, and a removed source can't be brought back except by adding it again. Removing a source never touches the original file in Google Drive. If you only want to leave a source out of answers for now, untick its checkbox instead.

Does NotebookLM have an API?

Not for personal accounts. Google offers a REST API for NotebookLM Enterprise, part of Google Cloud, and it's still marked as a pre-release version. Tools that claim to automate the consumer app are unofficial.

When to use something else

• You need answers beyond your files: the Gemini app, ChatGPT or Claude. See NotebookLM vs Gemini.
• You need to search a whole folder at once: a tool built for folders rather than notebooks.
• Your files can't leave your computer: an app that runs the model on your own machine.

Citenook covers the last two on a Mac. It reads whole folders in place, so there's no wall between notebooks and no source cap on higher plans; it keeps files up to date as you edit them; it can also add web pages and YouTube videos; and every answer links to the exact passage. With a model on your Mac, nothing is uploaded. It doesn't make Audio Overviews, quizzes or slides, and on-device models write simpler answers than Google's. See the full Citenook vs Gemini Notebook comparison.

Questions

Sources, checked 19 October 2026: Gemini Notebook Help on notebooks and sharing, adding sources, chat, notes, the mobile app, usage limits, plans and privacy; Google Cloud NotebookLM Enterprise API. Screenshot and citation test from our own notebook with made-up files.

Related: NotebookLM's source limits · How to use NotebookLM · NotebookLM vs Gemini