turbo-tasks: an internal panic occurred outside the per-task panic boundary.

[SarfDime]

thread 'tokio-rt-worker' (289812) panicked at turbopack/crates/turbo-tasks-backend/src/backend/operation/mod.rs:292:17:
Restore of All for task TaskId 168120 failed in another thread: restoring failed
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace

[KartikSharma4448]

The failure occurs while restoring Turbopack task state. That makes persistent-cache restoration a useful area to investigate, but this short log does not establish the root cause.

Could you share npx next info, your startup command, and the complete panic log/backtrace?

For a controlled test:

1. Stop the dev server and preserve the panic log.
2. Rename the generated .next directory to a backup name, then restart. Use your configured output directory if you changed distDir.
3. If that helps, restart again to check whether the problem returns when restoring the newly generated cache.
4. On versions supporting it, temporarily set experimental.turbopackFileSystemCacheForDev: false. This is a diagnostic test, not a confirmed fix.

You can also compare with npx next dev --webpack on Next.js versions supporting that flag.

If it reproduces with fresh output, please include a minimal reproduction and run with RUST_BACKTRACE=1. Redact secrets and sensitive paths before sharing logs.

References:

• Turbopack filesystem cache
• Next.js CLI

[SarfDime]

I cannot recreate the error now, and that .next was automatically deleted and manually deleted many times over since then.

But it did happen not long after i disabled experimental.turbopackFileSystemCacheForDev: false. So maybe it was just that i needed to clean .next before the issue?

Operating System:
  Platform: linux
  Arch: x64
  Version: #1 SMP PREEMPT_DYNAMIC Fri Sep 25 21:05:44 UTC 2026
  Available memory (MB): 15363
  Available CPU cores: 12
Binaries:
  Node: 24.21.0
  npm: 11.19.0
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 16.4.0 // Latest available version is detected (16.4.0).
  eslint-config-next: N/A
  react: 19.3.0
  react-dom: 19.3.0
  typescript: 7.0.2
Next.js Config:
  output: N/A

const nextConfig = {
  poweredByHeader: false,
  reactStrictMode: true,
  images: {
    remotePatterns: [
     ....
    ],
    formats: ['image/avif', 'image/webp'],
    deviceSizes: [480, 768, 810, 960, 1024, 1200, 1680],
    imageSizes: [16, 32, 48, 64, 96, 128],
    qualities: [65, 85, 91],
  },
  reactCompiler: true,
} satisfies NextConfig

const bundleAnalyzerConfig = withBundleAnalyzer(nextConfig)

export default bundleAnalyzerConfig