vercel/next.js · error

[Fast Refresh] performing full reload because your applicati

Error message

[Fast Refresh] performing full reload because your application had an unrecoverable error

What it means

Browser-side warning in the app-router hot reloader's handleApplyUpdates: applying the hot update failed (err), or a runtime error was already recorded by RuntimeErrorHandler, or the updated module list is null. Incremental Fast Refresh is unsafe in that state, so it logs this message and falls back to a full page reload (location.reload) to restore a working app.

Source

Thrown at packages/next/src/client/dev/hot-reloader/app/hot-reloader-app.tsx:164

// Attempt to update code on the fly, fall back to a hard reload.
function tryApplyUpdatesWebpack(sendMessage: (message: string) => void) {
  if (!isUpdateAvailable() || !canApplyUpdates()) {
    resolvePendingHotUpdateWebpack()
    dispatcher.onBuildOk()
    reportHmrLatency(sendMessage, [], webpackStartMsSinceEpoch!, Date.now())
    return
  }

  function handleApplyUpdates(
    err: any,
    updatedModules: (string | number)[] | null
  ) {
    if (err || RuntimeErrorHandler.hadRuntimeError || updatedModules == null) {
      if (err) {
        console.warn(REACT_REFRESH_FULL_RELOAD)
      } else if (RuntimeErrorHandler.hadRuntimeError) {
        console.warn(REACT_REFRESH_FULL_RELOAD_FROM_ERROR)
      }
      performFullReload(err, sendMessage)
      return
    }

    dispatcher.onBuildOk()

    if (isUpdateAvailable()) {
      // While we were updating, there was a new update! Do it again.
      tryApplyUpdatesWebpack(sendMessage)
      return
    }

    dispatcher.onRefresh()
    resolvePendingHotUpdateWebpack()
    reportHmrLatency(
      sendMessage,
      updatedModules,

View on GitHub (pinned to 258b1c1bc0)

Solutions

1. Fix the unrecoverable runtime error in your application; the page was fully reloaded to recover.

When it happens

Trigger: Thrown at packages/next/src/client/dev/hot-reloader/app/hot-reloader-app.tsx:164 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@258b1c1bc0 (2026-08-19). Data as JSON: /api/errors/4f07fc52aafec872. Report an issue: GitHub.