OneNote Copilot greyed out on Mac and missing in OneNote Web while Word Copilot works

Based on the context, this is a Copilot-availability/entitlement issue specific to OneNote rather than the account or license in general, because Copilot works in Word under the same account and on the same Mac.

From the available information, the following checks and actions are supported:

1. Confirm Copilot entitlement and account
   • Copilot in OneNote for Microsoft 365 is controlled by the same Copilot licensing and account validation as the other Microsoft 365 apps.
   • Ensure the signed-in account in OneNote for Mac and on the web is the same account that has the active Microsoft 365 subscription and Copilot Pro.
   • For home users, the account must have Microsoft 365 Personal or Family, or Copilot Pro. For business users, the account must have a supported Microsoft 365 subscription plus a Microsoft 365 Copilot license. See the account requirements in How to find and enable missing Copilot button in Microsoft 365 apps.
2. Refresh the license specifically from a Mac app Even though the license was refreshed, the supported way on Mac is:
   1. In any Microsoft 365 app on Mac (Word, PowerPoint, or OneNote), select the app name menu (for example, Word) at the top of the screen.
   2. Select About <app name>.
   3. Select More Info....
   4. Select Refresh License.
   5. Close all Microsoft 365 apps and reopen OneNote.
   This is the documented method in the Mac section of How to find and enable missing Copilot button in Microsoft 365 apps.
3. Verify privacy and connected experiences in OneNote for Mac Copilot can be blocked by privacy settings:
   1. Open Word on Mac.
   2. Go to Word > Preferences > Privacy.
   3. Ensure Experiences that analyze your content is turned on.
   4. Scroll down and ensure All connected experiences is turned on.
   These settings apply to Copilot across Microsoft 365 apps, including OneNote. If Microsoft 365 is managed by an organization, these settings may be controlled by the admin. This is described in the Mac privacy section of How to find and enable missing Copilot button in Microsoft 365 apps and in the causes listed in Copilot is missing, disabled, or doesn't work correctly.
4. Check OneNote on the web for license validation issues
   • On the web, Copilot relies on proper license validation and browser configuration.
   • If Copilot is missing in OneNote on the web while it works in Word, refresh the browser page.
   • If third-party cookies are blocked, Copilot may not be able to validate the license. Enabling third-party cookies is the documented workaround for Copilot license validation issues in the web apps. See the web section in How to find and enable missing Copilot button in Microsoft 365 apps and I am getting license validation errors with Copilot.
5. Confirm OneNote is on a supported build and channel
   • The context states that Copilot is available in OneNote for Microsoft 365 when the account has a Copilot license and the app is up to date.
   • For business users on Windows, the Semi-Annual Enterprise Channel blocks Copilot features; they must be on Current Channel or Monthly Enterprise Channel. While this specific channel note is documented for Windows, the general requirement is that the apps must be on a supported, current build. See the channel guidance in How to find and enable missing Copilot button in Microsoft 365 apps.
6. If Copilot remains greyed out only in OneNote Given that:
   • Copilot works in Word on the same Mac and account.
   • License refresh, privacy settings, and updates are already confirmed.
   • The issue reproduces in new notebooks and on the web version of OneNote.
   The remaining supported steps are:
   • Follow the generic Copilot-missing troubleshooting flow in Copilot is missing, disabled, or doesn't work correctly, which points back to the same “find and enable missing Copilot” article.
   • If the issue persists after all documented steps, contact Microsoft Support. For home users, the escalation path is explicitly recommended in I am getting license validation errors with Copilot. For business users, the Microsoft 365 admin should verify the Copilot license assignment and open a support case if necessary.

In summary, when Copilot works in Word but is greyed out or missing in OneNote for the same account, the supported resolution path is:

1. Confirm the correct Copilot-licensed account is active in all apps.
2. Refresh the license from a Mac app using the documented steps.
3. Ensure privacy and connected experiences are enabled.
4. For the web, refresh the page and allow third-party cookies.
5. Ensure apps are on a supported, current build.
6. If the issue persists only in OneNote after these steps, escalate to Microsoft Support, as this indicates a OneNote-specific Copilot activation/entitlement problem beyond the standard client-side fixes.

References:

• How to find and enable missing Copilot button in Microsoft 365 apps
• Copilot is missing, disabled, or doesn't work correctly
• I am getting license validation errors with Copilot
• Take notes with Copilot in OneNote
• Welcome to Copilot in OneNote