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Anthropic: Degraded functionality for Claude Cowork on Windows
Claude Cowork on Windows could not run local commands after a September 8 Windows update blocked workspace access to the computer’s drive; chat and file reading/editing still worked for most users. Anthropic rated the incident major, from 2026-09-10 15:54 UTC to 2026-09-14 19:14 UTC (4 days 3 h). Microsoft’s September 14 Windows update fixed it.
Machine-written from the archived incident (Sol). Check the timeline before relying on it.
Affected components: Claude Cowork
Timeline of updates
- identified
A Windows update released September 8 has left Claude Cowork on Windows unable to run local commands, because its workspace can no longer reach your computer's drive. For most users, chat and file reading and editing still work. There's no in-app workaround yet, and restarting or reinstalling won't help. Microsoft has developed a fix and is working to release it. We'll post an update when we have more to share.
- resolved
This issue has been resolved. Microsoft has released a September 14 Windows update that fixes it: https://support.microsoft.com/en-us/servicing/os/windows-11/2026/09/kb5129195-windows-11-24h2-25h2-security-update
Rewindex changes for this incident
- Major incident: Degraded functionality for Claude Cowork on Windows 2026-09-10 15:54 UTC
Impact, status and times are the vendor’s own, as last archived. View on stspg.io (opens in new tab). Anthropic profile · Recent Anthropic incidents · Markdown · JSON