---
format: "aidr-story-markdown/v1"
id: "215d5e6ee0fa4f77b5ab55fe519c54e23d8ff326193e9709b8c380c95faa0af5"
canonical_url: "https://aidr.today/215d5e6e?lang=en"
title: "If in doubt, delete the uv.lock file"
lang: "en"
requested_lang: "en"
available_langs: ["en","vi"]
translation_fallback: null
fallback_fields: []
published_at: "2026-11-01T23:24:22.000Z"
category: "Tools"
topics: ["coding","devtools"]
source_urls: ["https://simonwillison.net/2026/Nov/1/delete-uv-lock-first/"]
summary: "Deleting the uv.lock file can fix occasional confusing Python dependency errors when using Python 3.15. A specific error involved `watchfiles==1.1.1` failing because the configured Python interpreter version (3.15) was newer than PyO3's maximum supported version (3.14). Running uv run pytest again usually fixes the problem after deleting the file."
---

# If in doubt, delete the uv\.lock file

> [Open the canonical story](<https://aidr.today/215d5e6e?lang=en>)

**Published:** 2026-11-01T23:24:22.000Z
**Category:** Tools
**Topics:** coding, devtools

## Summary

Deleting the uv\.lock file can fix occasional confusing Python dependency errors when using Python 3\.15\. A specific error involved \`watchfiles\=\=1\.1\.1\` failing because the configured Python interpreter version \(3\.15\) was newer than PyO3's maximum supported version \(3\.14\)\. Running uv run pytest again usually fixes the problem after deleting the file\.

## Sources

- [Story source](<https://simonwillison.net/2026/Nov/1/delete-uv-lock-first/>)