# Prefect 3.8.6.dev1 — 3.8.6.dev1: Nightly Development Release

- Product: Prefect (https://whatsnew.fyi/product/prefect)
- Vendor: Prefect
- Date: 2026-09-05
- Version: 3.8.6.dev1
- Original notes: https://github.com/PrefectHQ/prefect/releases/tag/3.8.6.dev1
- Permalink: https://whatsnew.fyi/product/prefect/releases/3.8.6.dev1
- Labels: Pre-release

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **fixed** — Treat ERROR_ACCESS_DENIED as alive in Windows _is_pid_alive
- **fixed** — Rebuild invalid ix_event_resources__occurred left by an interrupted build

<!-- Release notes generated using configuration in .github/release.yml at main -->

##### What's Changed
###### Bug Fixes 🐞
* Treat ERROR_ACCESS_DENIED as alive in Windows `_is_pid_alive` by @devin-ai-integration[bot] in https://github.com/PrefectHQ/prefect/pull/23037
* Rebuild invalid ix_event_resources__occurred left by an interrupted build by @devin-ai-integration[bot] in https://github.com/PrefectHQ/prefect/pull/23033


**Full Changelog**: https://github.com/PrefectHQ/prefect/compare/3.8.5...3.8.6.dev1