[BUG] Cowork removes Claude for PowerPoint add-in after each session

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

What's wrong?
Every time Cowork is used to modify a PowerPoint file, the Claude for PowerPoint add-in disappears from PowerPoint. It needs to be manually re-deployed from the Microsoft 365 Admin Center (Settings > Integrated apps) after each Cowork session.

Steps to reproduce:

1. Deploy Claude for PowerPoint via Microsoft 365 Admin Center
2. Confirm the add-in is visible and functional in PowerPoint
3. Use Cowork to modify a Word document and a PowerPoint file in the same session
4. Open the PowerPoint file that was modified by Cowork
5. The Claude for PowerPoint add-in is no longer visible — even when opening a brand new PowerPoint document

Actual behavior:
The add-in disappears after every Cowork session involving PowerPoint. It must be re-deployed manually from the Microsoft 365 Admin Center each time. The issue is not limited to the Cowork-modified file — it also affects any newly opened PowerPoint document.

Additional context:

• The Claude for Excel add-in is still visible in the ribbon after Cowork sessions, but clicking it triggers the following error: "Microsoft 365 has been configured to prevent individual acquisition and execution of Office Store Add-ins." This suggests that Cowork may be altering the add-in execution context or registration for both Excel and PowerPoint.
• For PowerPoint, the add-in disappears entirely from the ribbon.
• For Excel, the add-in remains visible but becomes non-executable.
• The behavior is consistent and 100% reproducible.
• Platform: Windows, Microsoft 365

What Should Happen?

Expected behavior:
The Claude for PowerPoint add-in should remain deployed and visible in PowerPoint after a Cowork session, regardless of which file is opened.

Error Messages/Logs

Steps to Reproduce

Deploy both "Claude by Anthropic for Excel" and "Claude by Anthropic for PowerPoint" via Microsoft 365 Admin Center (Settings > Integrated apps)
Confirm both add-ins are visible and functional in Excel and PowerPoint
Open Cowork and run a task that involves modifying a Word document and a PowerPoint file in the same session
Once Cowork has completed, open the PowerPoint file that was modified by Cowork (or any new PowerPoint document)
Result for PowerPoint: the Claude add-in has completely disappeared from the ribbon
Result for Excel: the Claude add-in is still visible in the ribbon, but clicking it triggers the error: "Microsoft 365 has been configured to prevent individual acquisition and execution of Office Store Add-ins"
The only workaround is to manually re-deploy the PowerPoint add-in from the Microsoft 365 Admin Center — and repeat this after every Cowork session

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude 1.8555.2 (a476c3) 2026-05-22T23:04:37.000Z

Platform

Other

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_