Gemini Pro no longer able to use NotebookLM notebooks as a source (normal consumer Pro account)

Gemini API
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I am using a regular consumer Google account with Gemini Advanced (Pro, family plan). Until around mid-March 2026, I was able to use my NotebookLM notebooks as a source in Gemini chats and in custom Gems. It was not always perfect, but it basically worked: sometimes I got errors, but most of the time Gemini could access and use my NotebookLM content.

Since a few days, the integration seems to be completely broken for me:

  • When I start a new Gemini chat and attach a NotebookLM notebook as a source, Gemini either does not respond at all or responds as if there were no notebook attached.

  • When I try to use a NotebookLM notebook in a Gem, the Gem no longer appears to read from the notebook. It answers with generic model knowledge or does nothing, even for very simple questions that are clearly answered in the notebook.

  • NotebookLM itself is working fine. I can open my notebooks, chat inside NotebookLM, and get correct, grounded answers from the same sources. The problem only appears when Gemini is supposed to use NotebookLM as a source.

This used to work (with minor glitches) about two weeks ago, but now it has effectively stopped working entirely.

My setup:

  • Account type: regular personal Google account with Gemini Advanced (Pro, family plan)

  • NotebookLM: works normally when used directly

  • Gemini: works normally without NotebookLM, but fails as soon as a NotebookLM notebook is added as a source

From my perspective this looks like a regression in the Gemini ↔ NotebookLM integration on the server side, not a configuration or browser issue. It is also very similar to the “source blindness” / NotebookLM referencing bugs that other users have reported since the February 19 Gemini 3.1 Pro update.

Could you please:

  1. Confirm whether this is a known issue affecting consumer Pro accounts (not just Workspace)?

  2. Let us know if there is any current workaround (e.g., specific limits, smaller notebooks, switching model tier, etc.)?

  3. Provide an estimated timeline for a fix for NotebookLM as a data source in Gemini chats and Gems?

This integration is a key part of my workflow, so right now I have to fall back to working only inside NotebookLM and cannot reliably use Gemini with my notebooks.

Thank you for looking into this.