[BUG] Cowork file preview panel shows blank content (works in Chat)

[yheushen]

Preflight Checklist

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

What's Wrong?

Description
File preview panel in Cowork opens with the correct header/toolbar
but the content area is completely blank/white. The same file types
(PDF, etc.) preview correctly in Chat mode.

Steps to reproduce

1. Open a Cowork session
2. Generate or open any file (PDF, DOCX, etc.)
3. Click the file link — preview panel opens on the right
4. Header shows filename and Adobe Acrobat dropdown, but content is blank

Expected behavior
File content should render in the preview panel

Environment

• Claude Desktop version: 1.1.5749
• Plan: Max
• macOS: Sequoia 15.7.3
• Mac: MacBook Pro 16-inch 2023, M2 Max, 32GB RAM

Troubleshooting tried

• Updated app to latest version (1.1.5749)
• Restarted Mac
• Tested in a fresh Cowork session — same issue
• Confirmed preview works fine in Chat mode

What Should Happen?

File content (PDF, DOCX, HTML, etc.) should render and be visible in the Cowork preview panel, the same way it does in Chat mode.

Error Messages/Logs

Steps to Reproduce

1. Open any Cowork session
2. Ask Claude to create a file (e.g. "create a 1 page lorem ipsum PDF")
3. Click the file link in the response
4. Preview panel opens on the right — header/toolbar shows but content area is blank

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

N/A

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

This bug occurs in Claude Desktop (Cowork mode), not the API or CLI. The bug report template doesn't have a Claude Desktop option for Platform.

[github-actions]

Closing for now — this doesn't appear to be about Claude Code. Please open a new issue if this is still relevant.

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.