Dev server page becomes extremely slow / unresponsive in Microsoft Edge when DevTools is open (Vite 8, works fine after downgrading to Vite 5)

[kkclarson]

Describe the bug

When Microsoft Edge DevTools (F12) is open, the Vite dev server page becomes extremely slow and often becomes unresponsive — the page cannot be refreshed, and elements load with a delay of several seconds or more. The same app runs fine in Chrome with DevTools open, and fine in Edge without DevTools.

The issue is reproducible even with a very minimal app (Vue 3 + vue-router + Pinia + a couple of pages with Element Plus). No project code, plugin, or style causes it — see the isolation steps below.

Reproduction

1. Create a minimal Vue app with Vite 8 (@vitejs/plugin-vue 6.x).
2. Run vite (dev server).
3. Open the page in Microsoft Edge, press F12 to open DevTools.
4. The page becomes extremely slow: refreshes hang or take many seconds, DOM updates lag heavily.

Isolation / evidence

• Same project, same browser (Edge), only the build toolchain changed:
  • vite@8.3.0 + @vitejs/plugin-vue@6.0.8 → laggy / unresponsive with DevTools open
  • vite@5.4.21 + @vitejs/plugin-vue@5.2.4 → completely smooth
• A reference project running Vite 5 was tested side by side on the same machine and shows no issue in Edge DevTools.
• Chrome with DevTools open shows no issue on either version.
• The following were ruled out one by one while isolating (all disabled/tested individually, lag persisted until the Vite downgrade):
  • runtime config fetching (fetch of a JSON file before mount)
  • all plugin page code (only a bare layout + 404 page remained)
  • global styles / Sass
  • el-config-provider wrapper
  • unplugin-auto-import / unplugin-vue-components (auto-import disabled in dev)
  • Element Plus full import vs. on-demand import

System Info

System:
  OS: Windows 11
  CPU/GPU: x64 PC
Binaries:
  Node: 22.23.1
  npm: 10.9.8
Browsers:
  Microsoft Edge (latest, Chromium) — affected when DevTools is open
  Chrome — not affected
npmPackages:
  vite: 8.3.0 (affected) / 5.4.21 (fixed)
  @vitejs/plugin-vue: 6.0.8 (affected) / 5.2.4 (fixed)
  vue: 3.5.43

Used Package Manager

npm

Logs

No build or server errors are logged. The dev server starts normally (ready in ~850 ms); the slowness only manifests in the browser when Edge DevTools is open.

Expected behavior

The dev server should behave identically in Edge and Chrome regardless of whether DevTools is open, as it did with Vite 5.

[sagarcsnsw]

I have the same problem with Vite 8.2.0. I have another project with 7.3.1 and no problem

[parchon]

我也遇到了同样的问题，找了很多办法都不行
使用 chrmoe 一切正常的
vite: 8.0.10

[KiriRainCat]

#23549 (comment)
I had the same problem on Edge, but you can solve the issue temporarily with this method.