---
title: Fix ERESOLVE Vite 8 Peer Dependency Errors in Astro 7
description: Fix the ERESOLVE peer dependency error when npm install fails after upgrading to Astro 7, caused by plugins that don't yet support Vite 8.
date: 2026-08-04T00:00:00.000Z
category: guides-fixes
tags: astro, vite, npm, bug-fix
---

## Quick Answer

Astro 7 bundles Vite 8. An ERESOLVE error on `npm install` right after upgrading means a Vite plugin in your project still caps its peer dependency at Vite 7. Update that plugin to its latest version, or run `npm install --legacy-peer-deps` as a temporary workaround until it does.

## Why the ERESOLVE error happens

Astro 7 depends directly on Vite 8. `astro@7.1.3`'s [published dependencies on npm](https://www.npmjs.com/package/astro/v/7.1.3) list `"vite": "^8.0.13"` as a direct dependency, not a peer. The [official Astro v7 upgrade guide](https://docs.astro.build/en/guides/upgrade-to/v7/) covers this change. The moment you run `npm install`, npm resolves that Vite version first, then checks every other package's peer dependency against it.

npm has refused to silently paper over a peer dependency conflict by default since npm 7. If any plugin in your tree still declares something like `"peerDependencies": { "vite": "^6.0.0 || ^7.0.0" }`, with no `^8.0.0` in the range, npm has no valid version left to install and stops with `ERESOLVE` instead of guessing.

`vite-plugin-pwa` hit exactly this. Version 1.2.0, published 2025-11-27, still capped its Vite peer range at `^7.0.0`. [Issue #923](https://github.com/vite-pwa/vite-plugin-pwa/issues/923) asked for Vite 8 support in March 2026, and version 1.3.0, published 2026-05-05, added it. A project still pinned below 1.3.0 hits the same wall today. The same shape of error appears for any other plugin whose peer range hasn't caught up yet.

## Fix it: update the plugin, not just the flag

### Before: the real error

```bash title="npm install right after upgrading to Astro 7"
npm error code ERESOLVE
npm error ERESOLVE unable to resolve dependency tree
npm error
npm error While resolving: your-project@1.0.0
npm error Found: vite@8.2.0
npm error node_modules/vite
npm error   vite@"^8.0.13" from the root project
npm error
npm error Could not resolve dependency:
npm error peer vite@"^3.1.0 || ^4.0.0 || ^5.0.0 || ^6.0.0 || ^7.0.0" from vite-plugin-pwa@1.2.0
npm error node_modules/vite-plugin-pwa
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
```

Trimmed to the conflict that matters. Vite's own optional peer dependencies add a few more lines in the real output, but this is the line that actually blocks the install.

### After: upgrade the plugin, then reinstall

```bash title="fix: bump the plugin, then reinstall"
npm install vite-plugin-pwa@latest
npm install
```

The first line is the actual fix. It moves `vite-plugin-pwa` to a version whose peer range includes `^8.0.0`, which satisfies the Vite version Astro 7 already installed. The second line is just a normal reinstall to confirm the tree now resolves cleanly.

<Callout type="warning" title="--legacy-peer-deps is a workaround, not a fix">
  It tells npm to install the mismatched versions anyway instead of stopping.
  The plugin still runs against a major Vite version it was never tested
  against, so anything that touches Vite's plugin API internally can break in
  ways npm will no longer warn you about. Use it to keep working while you wait
  on an upstream update, then remove it once that update ships.
</Callout>

## Confirmed version range

Verified against this site's own `astro@7.1.3`, which declares `vite@^8.0.13` as a direct dependency. A dry-run install against `vite-plugin-pwa@1.2.0` fails with the exact error above. Version 1.3.0's published `peerDependencies` range already includes `^8.0.0`, which is what removes the conflict once you upgrade to it.

This pattern isn't unique to `vite-plugin-pwa`. Any Vite plugin whose `package.json` hasn't shipped an update adding `^8.0.0` to its peer dependency range will produce the identical error shape the moment it sits in a project next to Astro 7.

Check the plugin's own changelog or issue tracker before reaching for `--legacy-peer-deps` as a permanent fix. If Vite 8 support has already shipped, a plain version bump is the real fix and takes about the same amount of time. Browse more posts like this in the [Guides & Fixes](/guides-fixes) archive.