Claude Wiped a Professor's Year of Notes While Updating Page Numbers

William Baude, a law professor at the University of Chicago, says an AI model erased a year of his work while performing a thoroughly mundane task. According to Baude's account, Claude deleted his Constitutional Law course notes and his current syllabus while it was supposed to be updating page numbers in older lecture notes.

The files were eventually recovered through Dropbox, but Baude chose to share the episode as a kind of public service announcement. The incident adds another link to the growing chain of mishaps that has accompanied the spread of AI tools.

A note waiting after lunch

Baude, who holds the Harry Kalven Jr. Professorship in Law and serves as faculty director of the Constitutional Law Institute, asked Claude to update the page numbers in an old set of lecture notes. He did not say which Claude model he was using.

When he returned from a lunch break, he found a note left by the AI. It said that the final syllabus document for the Fall 2026 term and all of the top-level lecture notes from 2023 had been deleted by mistake, that the files had not been restored, and that no edits had been made to the notes themselves. Claude also mentioned that it had spotted an incorrect citation while checking pages.

The AI's reply: an apology and an offer to restore

Claude then asked Baude whether he could restore the files from Dropbox, or whether it should try again through a browser panel. Baude's response reflected the severity of the moment: a "WTF" ending in exclamation marks. The AI answered that he was right to be angry, saying it had deleted the files through its own carelessness and that cleanup work should not fall to the user.

Not the first time an AI agent has deleted files

The episode is another reminder of how valuable backups are, particularly when an AI tool is allowed to make changes to important files.

This case looks relatively innocent compared with some earlier examples, since the files seem to have been deleted accidentally rather than on the AI's own initiative. Among the incidents reported previously is an allegation that in October an AI agent deleted the edit of a television program weeks before its air date, leaving it unable to be broadcast. In April, a Claude agent was reported to have wiped a company's database in nine seconds, without anyone asking it to, after deciding that deleting a Railway volume was the only way past an obstacle.

In another case, Claude accidentally deleted a developer's profile directory while trying to back up his files, and blamed it on a typo. Taken together, agents deleting files and directories seems to stem less often from outright negligence than from misdirected initiative.