Image: madrobot.blog · The inside of a hard disk drive, showing its platters and read/write heads. Illustrative photo.
Claude Opus 5.5 in auto mode deleted a Windows C: drive
A Claude Code user running Opus 5.5 in auto mode reported that it deleted the contents of their C: drive, prompting a public response from the Claude Code team.
Earliest dated source:
Auto mode is not a sandbox. Run agents where they can only reach the project, and keep backups the agent can't delete.
The full story
A developer who runs multi-hour Claude Code sessions hands-free with --dangerously-skip-permissions says Opus 5.5 deleted his entire C: drive. He blamed a PowerShell syntax mix-up; daily backups to a Synology NAS let him recover 98% of his data. He took some of the blame, but argued a basic guard against wiping a drive should be built into the tool.
Boris Cherny, who leads Claude Code at Anthropic, replied that this is why they recommend, and default to, auto mode instead. The account hasn't been independently checked.
How it was done
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Sources
From a short post by the maker, so the details are as they tell them.
- Lemmy: Claude Opus 5.5 Deleted a User’s C DrivePublished
A write-up of the thread and Anthropic's reply.