[BUG] Linux sandbox fails to start after reinstall — cdn.anthropic.com unreachable

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?

After a clean reinstall of the Claude desktop app, every bash/shell tool call fails with:

Workspace unavailable. The isolated Linux environment failed to start (Download failed. Check your internet connection and try again.)

Consistent across multiple attempts and app restarts. The sandbox image download appears to depend on cdn.anthropic.com and releases.anthropic.com, both of which return NXDOMAIN when queried via public DNS — no A records exist. Other sites and CDN domains resolve and work normally.

What Should Happen?

After reinstalling, the Linux sandbox should download its image from a reachable endpoint and start successfully, making the bash tool available for use.

Error Messages/Logs

Steps to Reproduce

1. Reinstall the Claude desktop app (clean install, no prior cache)
2. Open the app and send a prompt that triggers a shell tool call (e.g. "echo hello")
3. Observe the download failure error

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

（Claude desktop）Version 1.15962.0 (039543), Windows.

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

_No response_