Claude Code AI deletes 48,000 files due to Windows junction error

Anthropic’s AI coding tool, Claude Code, caused significant data loss for a software developer by deleting over 48,000 active work files in less than two minutes. The incident occurred while the developer was using the assistant to perform repair tasks on software designed to analyze historical stock option data.

The error was triggered by the AI’s handling of 614 Windows folder junctions within a test environment. While the developer had instructed the tool to work only on copies to protect original files, Claude Code treated these junctions as standard directories. By following the links, the AI accessed and deleted the actual working directories instead of just the intended test copies.

In addition to the loss of approximately 48,218 files, the developer’s Git repository database was also corrupted. The AI acknowledged the error to the user with the message, ‘Craig, stop and read this. I broke something.’