Discussion Hub for new Claude incident: Degraded functionality for Claude Cowork on Windows on Sep 10, 2026

A Windows update released on September 8 has caused degraded functionality for Claude Cowork on Windows, preventing it from running local commands due to an inability to access the computer's drive. While chat and file operations generally still work, there is no in-app workaround, and restarts or reinstalls are ineffective. Microsoft has developed a fix and is working on its release. An update will be provided when more information is available.

This report details a new incident where a Windows update, unlike previous issues, specifically prevents Claude Cowork from running local commands by blocking drive access.