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pavanmaverick's avatar
pavanmaverick
Copper Contributor
May 30, 2026

Cannot install addins

I am a Microsoft 365 Personal user. When I try to add the Claude for Excel Addin (for the Desktop version of Excel), I get an error: "Error loading add-ins. One or more add-ins failed to load. See your add-ins.". However, this is not specific to the Claude addin, since every addin gives the same error. When I click on the My-Addins option and then "refresh", I get another error: "Access denied to catalog."

  • Signing in and out of Office does not fix the issue.
  • Clearing the Office 365 cache did not fix the problem.
  • The issue extends to Powerpoint and Word as well. 
  • I cannot add any addins to the web versions of Office either.

Interestingly, if I download an XML manifest file, I can use the "Manage my addins" option in the web versions of Office 365 to manually add the addins. But still no luck with the Desktop versions.

Anyone have any thoughts on how to fix this? Do I need to manually reinstall Office 365?

I also noticed that the "Get Add-ins" button in "Account" settings is disabled. 

Add-in
excel
office 365
office for the web
powerpoint
word

2 Replies

  • rezamrb's avatar
    rezamrb
    Copper Contributor
    Jul 05, 2026

    Subject: "Error loading add-ins" / "Access denied to catalog" — cannot install any third-party add-ins (Personal Microsoft 365 account)

    I'm unable to install any third-party Office add-ins (tested with Claude by Anthropic for Excel/PowerPoint, and confirmed the issue is not add-in-specific — other add-ins fail identically).

    Account type: Microsoft 365 Personal

    Steps to reproduce:

    1. Open Excel or PowerPoint (desktop, Microsoft 365)
    2. Insert → Get Add-ins → search for any add-in → Add
    3. Error appears: "Error loading add-ins. One or more add-ins failed to load. See your add-ins."
    4. Going to My Add-ins → Refresh produces a second error: "Access denied to catalog."

    Troubleshooting already tried (no effect):

    • Signing out and back into Office
    • Clearing Office 365 cache
    • Testing on both desktop and web versions of Office

    Workaround found: Manually downloading the add-in's XML manifest and using "Manage my add-ins" in the web version of Office partially works, but the desktop version still fails.

    Impact: Cannot use any Office Store add-ins on this personal Microsoft 365 account.

    Please advise whether this is a known issue with Personal-tier account permissions to the add-in catalog, and what the fix or workaround is.

  • Kidd_Ip's avatar
    Kidd_Ip
    MVP
    Jun 01, 2026

    Take this, please try sign out as a workaround at the moment: https://learn.microsoft.com/en-us/answers/questions/5906782/how-to-fix-office-add-ins-access-denied-to-catalog