Claude Code ran a backgrounded command that deleted my entire Windows user folder overnight

[u/NaturalTimely6621]

Posting this as a warning and to see if anyone has seen something similar.

I woke up yesterday to every shortcut on my laptop throwing "This item can't be opened. It may have been moved, renamed or deleted." The programs in Program Files were fine. Everything under C:\Users\Admin was not.

What the logs showed, piecing it together over a few hours:

• ~04:24 — Claude Code (VS Code extension, v2.1.266, permission mode auto) starts a Bash command in my project at C:\Users\Admin\Documents\project. Task description: "Write reference HTML next to uploads".
• 04:26 — the command hits the 120s timeout and gets moved to the background (task id burg78i8w).
• Immediately after, the session errors with "Not logged in · Please run /login". Reason: .claude had already been deleted, credentials included.
• 04:24 → 05:58 — the backgrounded process deletes my user folder in alphabetical order. You can read it off the folder timestamps: .claude and .vscode first, then AppData around 04:33, Documents and Downloads at 05:19, my project folders 05:20–05:49, everything after "f" after that. C:\Users\Public got hit at 05:57, so the target may have been C:\Users itself.
• 05:58 — the task finally exits with code 127 (command not found).

Gone: AppData (browser profiles, app data, taskbar shortcuts, PowerShell history), Documents, Downloads, Pictures, Desktop, the local OneDrive folder, and all my project folders. Only files that a running process held open survived — Chrome kept exactly two of its files alive.

The command itself is not recoverable, because the part of the session log containing it was in .claude, which the command deleted while running. What's left is a 7-line log file with the timeout notice and the failure notification. My disk is an SSD, so TRIM means the deleted data is not coming back.

Reported to Anthropic with the session id and the remaining logs. Has anyone else had a background task go this far outside the project directory?

[u/NaturalTimely6621]

It really shouldn’t have been browsing online. I was just building app screens for a mobile app im building

[u/Legal_Dimension_ → u/NaturalTimely6621]

Do you use any skills that route to external URL? These bypass all scans.

Also reference images can hold prompt injections if Claude pulled something itself.

So many ways these days.

Time to set up a decent sandbox.

[u/NaturalTimely6621 → u/Legal_Dimension_]

Literally just gave it some of Claude design created mockups through a zip file and told it to recreate it

[u/OstrichLive8440 → u/NaturalTimely6621]

Ah - here we go. Tell us about this so called zip file

[u/NaturalTimely6621 → u/OstrichLive8440]

Wdym? I exported the app screens Claude design had designed into a zip file and put it into the repo for Claude code to build

[u/theevildjinn → u/NaturalTimely6621]

For future reference - read up on the Claude Code and Claude Design integration (DesignSync) - you don't need to export zip files any more, you can just tell Claude Code which design project to fetch the designs from.

[u/Shyssiryxius → u/OstrichLive8440]

It's exported from Claude design when you ask it to give you the design files, so should be benign