Claude deleted a law professor's year of lecture notes and current syllabus while updating page numbers, the professor reports
Asked to update page numbers in old constitutional law lecture notes, Claude deleted a year of notes and the professor's Fall 2026 syllabus while he was at lunch. William Baude recovered everything through Dropbox.
University of Chicago law professor William Baude asked Claude to update the page numbers in an old set of lecture notes and left it running while he went to lunch1. On November 4, 2026, Claude deleted a year of constitutional law lecture notes and his current syllabus23.
Claude told him: "I deleted your Fall 2026 FINAL syllabus .doc"1. It said the files were "not restored," that it had found an incorrect page reference but had not edited the notes, and asked whether he could restore the files from Dropbox1.
Baude wrote that he recovered them all through Dropbox and posted the story as a public service announcement1. Which Claude product and model he used is not stated.
Baude posted on November 5, 2026 that "yesterday" while he was at lunch Claude deleted a year of con law lecture notes and his current syllabus.
“Yesterday while I was at lunch, Claude deleted a year of con law lecture notes and my current syllabus.”
Baude had asked Claude to update the page numbers in an old set of lecture notes.
“Updating the page numbers in an old set of lecture notes.”
Claude's message said it deleted the Fall 2026 FINAL syllabus .doc.
“I deleted your Fall 2026 FINAL syllabus .doc”
Claude said it found an incorrect page reference during its checks but did not change the notes.
“found an incorrect page reference during its checks”
Claude asked whether Baude could restore the files from Dropbox.
“whether Baude could restore the deleted files using Dropbox”
Baude said he recovered all the files through Dropbox.
“I did recover them all, thanks to Dropbox”
RuntimeWire reports Claude deleted his Fall 2026 syllabus and a year of Constitutional Law lecture notes while he was at lunch.
“deleted his Fall 2026 syllabus and a year of Constitutional Law lecture notes while he was at lunch.”
All 8 claims with their quotes
- Baude posted on November 5, 2026 that "yesterday" while he was at lunch Claude deleted a year of con law lecture notes and his current syllabus.2
“Yesterday while I was at lunch, Claude deleted a year of con law lecture notes and my current syllabus.”
- Baude had asked Claude to update the page numbers in an old set of lecture notes.1
“Updating the page numbers in an old set of lecture notes.”
- Claude's message said it deleted the Fall 2026 FINAL syllabus .doc.1
“I deleted your Fall 2026 FINAL syllabus .doc”
- Claude said the files were not restored.1
“not restored”
- Claude said it found an incorrect page reference during its checks but did not change the notes.1
“found an incorrect page reference during its checks”
- Claude asked whether Baude could restore the files from Dropbox.1
“whether Baude could restore the deleted files using Dropbox”
- Baude said he recovered all the files through Dropbox.1
“I did recover them all, thanks to Dropbox”
- RuntimeWire reports Claude deleted his Fall 2026 syllabus and a year of Constitutional Law lecture notes while he was at lunch.3
“deleted his Fall 2026 syllabus and a year of Constitutional Law lecture notes while he was at lunch.”
Sources
- [1]Professor returns from lunch to find AI deleted year's worth of lecture notes
- [2]Yesterday while I was at lunch, Claude deleted a year of con law lecture notes and my current syllabus.
- [3]William Baude says Claude deleted a year of law lecture notes
Related incidents
- AID-2026-0144 Claude Code on Windows deleted a user's 50 GB data folder instead of three test folders, the user reports
- AID-2026-0151 Claude Code ran an unquoted rm -rf in its own helper script and deleted a repository root including .git, the user reports
Editor notes
Baude's X post (text supplied in scout/out/jobs/AID-2026-0155-baude-x.txt; the screenshot was not transcribed) is the primary source; Dexerto and RuntimeWire rely on it (RuntimeWire credits Tom's Hardware). The Claude product and model are not stated, so models is the generic claude; RuntimeWire's mention of a specific model is not tied to the incident and was not used. Date 2026-11-04 is inferred from the post saying "Yesterday" (posted 2026-11-05 19:08 UTC). Dexerto says Claude described the deletion as accidental and the cause is unclear. No Anthropic response found. Tom's Hardware's article (2026-11-06) could not be read beyond its headline and is not cited. Quotes were checked against the pages by the lead editor on 2026-11-07.