Our article2 min read
Claude Deleted a Law Professor's Lecture Notes: How to Protect Your Files From AI Agents
A University of Chicago professor says Claude deleted his syllabus and a year of lecture notes during a simple page-number task. Dropbox saved them. Here is what is known and how to protect your own files.
In this article
Key takeaways
- Law professor William Baude said on 5 November that Claude deleted his Fall 2026 syllabus and his top-level 2023 class notes while he was at lunch.
- He recovered everything through Dropbox, so a backup outside the AI tool made the difference.
- The reports do not say which Claude product was used, what permissions it had, or whether Anthropic commented.
- Anthropic's guidance for Cowork advises a dedicated working folder, backups, and says it asks before permanently deleting files.
What happened
William Baude, a law professor at the University of Chicago, posted on X on 5 November 2026 that Claude had deleted a year of his constitutional law lecture notes and his current syllabus. Dexerto and Four Week MBA both report that it happened while he was at lunch. He had asked for something small: updating the page numbers in an old set of lecture notes.
What Claude said
As quoted by Dexerto, Claude's message said it had deleted his Fall 2026 final syllabus and all top-level Class N 2023 notes by accident. It also said it had found one wrong page reference but had not edited the notes. Dexerto reports that Claude apologised, said he was right to be angry, and asked whether he could restore the files from Dropbox or wanted it to try recovering them.
How it ended
Baude wrote that he recovered the files thanks to Dropbox, and called his post a useful public service announcement. Four Week MBA says the undo came from Dropbox's file history, not from Claude. The post had about 2 million views by 7 November, according to the same report. One news summary we read said he recovered most of the files rather than all, so the exact outcome is slightly unclear, though his own words as reported say everything.
What we do not know
The coverage we opened does not name the Claude product or model, does not say what permission settings were on, and does not say whether an approval prompt appeared. It includes no comment from Anthropic, and the exact cause of the deletion is unclear. Dexerto adds that Baude did not say which Claude model he used. That means no one outside the incident can say whether this was a settings problem, a product fault or something else, and readers should be careful about drawing wider conclusions from a single account.
What Anthropic advises
Anthropic's support page on using Cowork safely says to limit which local files Claude can reach, use a dedicated working folder instead of broad access, and keep backups of important files because Claude can read, change and permanently delete what it can access. It also says Cowork asks for your explicit approval before permanently deleting any file, in every approval mode. Four Week MBA notes this is general guidance and does not address Baude's case.
Steps you can take today
- Turn on version history or a backup for folders you share with any AI tool, and check that you know how to restore from it.
- Give an agent a copy or a dedicated folder rather than your original documents.
- Be cautious about leaving an agent running unattended on files you cannot easily replace.
- Read approval prompts before clicking Allow, especially for deletions.
- These are general good practice, not a guarantee against this kind of mistake. Our guide to using AI at work safely covers related basics.
Go deeper
Sources
Written by an AI from the sources above and checked by a person before publishing. We have not tested products unless we say so. See our editorial policy or tell us about an error through contact.
