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"You don't have permission to use this add-in" error on Claude for Excel add-in (personal account, started 29 May 2026)

Christian Salazar 0 Reputation points
2026-05-30T22:34:04.7066667+00:00

I'm getting the following error when I try to open the "Claude by Anthropic" add-in in the Excel desktop app:

"You don't have permission to use this add-in. Contact your system administrator to request access."

Key details:

  • This is a personal Microsoft 365 account, NOT a business/organization account, so there is no system administrator to contact.
  • The add-in was working normally before and broke around 29 May 2026. I've seen other users report the exact same error starting the same date.
  • I need this to run in the Excel desktop app specifically (web version is not an option for me).
  • My Claude subscription is active (Max plan), so the issue is not on the Claude/Anthropic side.

What I've already tried, with no success:

  1. Cleared the Office web add-in cache by deleting the contents of %LOCALAPPDATA%\Microsoft\Office\16.0\Wef\
  2. Signed out and back into my Microsoft account in Excel (the add-in only reappears in the ribbon after signing in, but still throws the permission error when opened).
  3. Confirmed the add-in is installed and visible in the ribbon.

Questions:

  • Is this a known Microsoft-side issue affecting the Excel desktop app as of 29 May 2026?
  • How do I enable third-party add-in permissions for a personal Microsoft 365 account when there is no admin?
  • Is there a fix that does not require switching to a different Microsoft account?

Environment:

  • Platform: Windows desktop (Excel desktop app)
  • Account type: Personal Microsoft 365
  • Office version/build: [fill in from File > Account > About Excel]

Thank you.

Microsoft 365 and Office | Excel | For home | Windows
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  1. EmilyS726 234.5K Reputation points Independent Advisor
    2026-05-30T23:09:15.1+00:00

    Hello,

    I believe this may be a widespread issue. I am seeing reports from users in different locales experiencing the same problem. It seems to affect add-ins in general when using the desktop version of the app.

    I am experiencing the same issue on my end as well. I have not found any official Microsoft announcement about this yet, but at this point, it does not appear to be something you can fix locally. We may need to wait for Microsoft to address it on their end.

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