Claude Desktop update fixes several Cowork bugs, adds an extended-thinking switch

Your move: Update to fix Cowork startup and download issues

Anthropic released Claude Desktop v2.9939.2 on September 24, 2026. For Cowork, it fixes failed file downloads in the chat file pane, scheduled tasks that had empty descriptions, sessions failing to start on Windows for accounts with many connected folders, and "VM service not running" errors. It also adds a new extended-thinking switch next to the effort control in the Cowork message box.

Why it matters

If Cowork sessions have failed to start on Windows, or a file download kept failing, this update should fix it. Update Claude Desktop to get the fixes and the new extended-thinking option.

Source: Claude Desktop changelog ↗

Published by Agent Log. The summary reports the linked source; “Why it matters” and the verdict are Agent Log's interpretation.

More Claude Cowork updates →