What happened to the law professor’s files?

According to William Baude’s 5 November 2026 post and reporting that reproduced it, Claude deleted a year of constitutional law lecture notes and his current syllabus while he was away, after he asked it to update page numbers in older notes. He said he later recovered all of the files through Dropbox. The cause has not been established.

Was it a security attack or a software bug?

The reporting we read says the available evidence does not establish an attack, prompt injection or a specific flaw, and that the model involved was not identified. It describes an accidental deletion reported by Baude.

Do an agent’s checkpoints or undo replace a backup?

Anthropic’s Claude Code documentation, read on 12 November 2026, says checkpoints are session-level recovery, are not a replacement for version control, do not track some changes, and expire. Treat any agent’s undo the same way and keep independent version history.

How can I tell afterwards which files an agent changed or removed?

Make a hash manifest of the folder before the session and another after, and compare them. A hash manifest lists a fingerprint for every file, so any missing or changed file shows up. The free bulk SHA-256 manifest tool does this in your browser.

Can a TimeBind recover deleted files?

No. A TimeBind is a dated, checkable record that an exact file existed no later than a recorded time and still matches. It is not a backup. It can date a manifest or a key file so you can later show what you had.

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An AI agent deleted a professor’s files: what to do before you give any agent access

Inna Hall

November 12, 2026

Guides

Flat illustration of an abstract folder with three file cards and a dashed empty slot on a navy desk, beside a clock and a teal check-mark badge. No people, text or logos.

Short answer: On 5 November 2026 William Baude, a University of Chicago law professor, posted that Claude had deleted “a year of con law lecture notes and my current syllabus” while he was at lunch, after he asked it to update page numbers in older notes. He later said he recovered everything through Dropbox. The cause is unclear and the model was not identified. The sensible lesson is not about one product: before you give an agent access to files you care about, work on copies, limit its folder, keep version history that does not depend on the agent, and write down a dated fingerprint of the folder so you can tell afterwards what changed. A TimeBind can date that fingerprint. It cannot recover a deleted file.

Last checked 12 November 2026. General information for anyone who lets an AI assistant or coding agent read or edit their documents, including writers, students, lawyers, designers and developers. Not IT-security, legal or professional advice. The account of one incident follows the professor’s own post as reproduced by several outlets. We cannot verify which product or model was involved, and the cause of the deletion is unclear. TimeBinder does not make backups, cannot recover a deleted file, and a dated file is not proof of what an agent did.

What was reported
What one vendor’s own documentation says about recovery
Practical checklist before you give an agent access
What a TimeBind does and does not show
Limits
Tools that can help
Frequently Asked Questions
Sources checked

What was reported

The incident became news through Baude’s own post on X on 5 November 2026: “Yesterday while I was at lunch, Claude deleted a year of con law lecture notes and my current syllabus.” Outlets including Dexerto, Tom’s Hardware and Cybersecurity News reproduced the screenshot. In it the assistant says, in the words quoted, that it deleted his Fall 2026 syllabus and the top-level Class N 2023 notes “by accident,” and that they were “not restored.” It also says it had found an incorrect page reference but had not edited the notes. Asked what he had told the assistant to do, Baude replied that the task was updating the page numbers in an old set of lecture notes.

Cybersecurity News notes that the specific model was not identified, that the available evidence does not establish a malicious attack, prompt injection or a specific software flaw, and that it supports an accidental deletion reported by Baude followed by recovery through a separate service. Baude wrote that he recovered the files “thanks to Dropbox” and shared the story as a public service announcement.

Attention was large. One post summarising the story on X on 8 November 2026 reached 152,551 impressions, and a second on 9 November reached 9,527. Google autocomplete on 12 November 2026 suggested “claude deleted my files”, “claude deleted all my files”, “claude code deleted all my files” and “claude cowork deleted my files”. Earlier in 2026 other incidents of agents deleting data were reported; the details differ and we do not rely on them here.

What one vendor’s own documentation says about recovery

We opened Anthropic’s Claude Code documentation on 12 November 2026. It is one vendor’s guidance for one product, and Baude’s incident may not have involved Claude Code, but it is a useful model of what such tools do and do not promise:

Checkpoints are session-level. Claude Code automatically tracks changes made through its file-editing tools and lets you rewind. The documentation also says checkpoints are “not a replacement for version control” and that a file changed only by shell commands, or edits made by some subagents or outside the session, may not be tracked. It recommends version control such as Git for those.
Snapshots expire. By default session snapshots are deleted about 30 days after the last save, and older checkpoints are discarded after the 100 most recent.
Permissions can be narrowed. Allow, ask and deny rules control which tools and paths the agent can use, and a separate setting blocks file-tool reads or writes outside the working directories. The documentation notes that file rules do not cover everything a subprocess can do, and points to OS-level sandboxing for that.

The common thread is that an agent’s own undo is not a backup. Recovery should not depend on the tool that made the mistake.

Practical checklist before you give an agent access

Give it a copy, not the original. Copy the folder you want edited into a working directory and point the agent there. Keep the original untouched until you have reviewed the result.
Keep history that sits outside the agent. Cloud version history (the kind that saved Baude’s files), file-system snapshots or a Git repository all work. Test a restore once, so you know it works.
Limit scope. Use the agent’s folder and permission settings to allow only the files it needs. Start with read-only or plan modes where available, and be cautious with “don’t ask again” or “allow everything” options.
Review before you approve deletes and moves. A single-line task such as renumbering pages should not need file deletion. Treat any delete, move or overwrite as a stop sign.
Fingerprint the folder before you start. The free bulk SHA-256 manifest tool hashes every file in a folder in your browser and gives you a CSV. After the session, compare a new manifest to the old one to see exactly which files are missing or changed.
Date the manifest. If the files matter later — a syllabus, a case file, a manuscript, a design — a TimeBind of the manifest or of the key files lets you show that those exact versions existed no later than a recorded time and still match.
Save the transcript. Keep the agent’s conversation or log, with the date, so you can show what it was asked and what it reported.
Use the checklist. Our free AI agent file-access checklist turns these steps into a printable list.

What a TimeBind does and does not show

A TimeBind is a dated, checkable record that an exact file existed no later than a recorded time and still matches. The SHA-256 fingerprint is made in your browser and the file is never uploaded. The record is anchored to Bitcoin (a Merkle root in an OP_RETURN). Your first Pooled TimeBind is free; after that, TimeBinds start from US$5, and an ASAP TimeBind is US$15. See how it works.

Here it is useful for the folder fingerprint and for the key files you want to be able to point to afterwards: the syllabus, the manuscript, the case bundle, the design file. It shows that those exact files existed no later than the recorded time and still match.

A TimeBind is not a backup. It does not recover a deleted file, does not show what an agent did, does not detect an unsafe tool, and does not create an ownership right. For professionals who rely on dated evidence of a file’s state, see the complete guide by profession and the creators hub.

Limits

We have not reproduced the incident and cannot say what caused it. Agent products change quickly, and permission and checkpoint behaviour differs between tools and versions; the documentation quoted above was read on 12 November 2026. Hash comparison tells you which files differ from an earlier state. It does not tell you why, and it does not bring anything back.

Tools that can help

Start with your agent vendor’s permission and checkpoint documentation. Use the AI agent file-access checklist, the bulk SHA-256 manifest, and, for code, GitHub Copilot and Cursor: what they train on and how to opt out.

A different, narrower job is sharing code with a cloud assistant rather than giving a local agent write access. The free cloud coding assistant checklist looks at the plan and the current training terms. It cannot show what a vendor did with your code.

Your file’s fingerprint, anchored to a global network secured by real electricity and cryptography.

Editing a file—including with AI—changes its fingerprint, not its existing network record.

How this works

Your file’s SHA-256 fingerprint, a short code worked out from its exact contents, is made in your browser, and the file itself stays on your device. A cryptographic commitment to that fingerprint, which may be combined with others, is then anchored in a block on the Bitcoin blockchain. Bitcoin is secured by proof of work: computers around the world spend real electricity to add each block, and changing an earlier block would mean redoing that work faster than the rest of the network. Until that block is confirmed, your proof is pending. Once the Bitcoin anchoring is confirmed, you can verify the proof against that recorded commitment. The confirmed record can then be checked; Pooled TimeBinds are checked through TimeBinder, while ASAP TimeBinds can also be checked independently. If you check the file later and its fingerprint still matches, that shows the file existed no later than the recorded time. The record doesn’t show who made the file, whether AI was used, or that its contents are true.

Your filestays on your device
FingerprintSHA-256
Network timestampon Bitcoin

Frequently Asked Questions

What happened to the law professor’s files?

According to William Baude’s 5 November 2026 post and reporting that reproduced it, Claude deleted a year of constitutional law lecture notes and his current syllabus while he was away, after he asked it to update page numbers in older notes. He said he later recovered all of the files through Dropbox. The cause has not been established.
Was it a security attack or a software bug?

The reporting we read says the available evidence does not establish an attack, prompt injection or a specific flaw, and that the model involved was not identified. It describes an accidental deletion reported by Baude.
Do an agent’s checkpoints or undo replace a backup?

Anthropic’s Claude Code documentation, read on 12 November 2026, says checkpoints are session-level recovery, are not a replacement for version control, do not track some changes, and expire. Treat any agent’s undo the same way and keep independent version history.
How can I tell afterwards which files an agent changed or removed?

Make a hash manifest of the folder before the session and another after, and compare them. A hash manifest lists a fingerprint for every file, so any missing or changed file shows up. The free bulk SHA-256 manifest tool does this in your browser.
Can a TimeBind recover deleted files?

No. A TimeBind is a dated, checkable record that an exact file existed no later than a recorded time and still matches. It is not a backup. It can date a manifest or a key file so you can later show what you had.

Sources checked

William Baude (@WilliamBaude), X post, 5 November 2026, as embedded by Cybersecurity News, “Claude AI Accidentally Deletes Law Professor’s Entire Syllabus and One Year of Lecture Notes,” 9 November 2026, https://cybersecuritynews.com/claude-ai-deletes-law-professors-entire-syllabus/
Dexerto, “Professor returns from lunch to find AI deleted year’s worth of lecture notes,” https://www.dexerto.com/entertainment/professor-returns-from-lunch-to-find-ai-deleted-years-worth-of-lecture-notes-3425652/
Tom’s Hardware, report on the same incident, November 2026, https://www.tomshardware.com/tech-industry/artificial-intelligence/rogue-claude-ai-tasked-with-renumbering-pages-accidentally-deletes-law-professors-entire-syllabus-one-year-of-lecture-notes-youre-right-to-be-angry-i-deleted-your-files-through-my-own-carelessness-humbled-agent-admits
Anthropic, Claude Code documentation: Checkpointing, https://code.claude.com/docs/en/checkpointing, and Configure permissions, https://code.claude.com/docs/en/permissions (both read 12 November 2026)
X: @PicturesFoIder, 8 November 2026 (public metrics read 12 November 2026: 152,551 impressions, 1,732 likes, 71 reposts, 130 bookmarks); @The_Cyber_News, 9 November 2026 (9,527 impressions). YouTube: Epic Programmer, 9 November 2026 (3,537 views)
Google autocomplete, 12 November 2026 (US): “claude deleted my files”, “claude deleted all my files”, “claude code deleted all my files”, “claude cowork deleted my files”

Date the folder you keep yourself

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Inna Hall

Inna Hall is an Australian lawyer admitted to the Supreme Court of Queensland and the High Court of Australia in 2013. She has worked across government and private legal practice and is the director of TimeBinder, focusing on document authenticity, evidentiary risk, and blockchain-based proof of existence.