---
title: Instant Navigation validation errors
url: "https://nextjs.org/docs/messages/instant-navigation-validation"
docs_index: /docs/llms.txt
---



Instant Navigation validation checks whether a route can produce the UI required at each [navigation stage](/docs/app/glossary#navigation-stages). This page collects the errors and non-blocking insights it can report.

## Debug validation errors

Start with [`next dev`](/docs/app/guides/building#find-blocking-work) and open the affected route. The development overlay and terminal show source-mapped stack frames and rerun validation as you edit.

If the error only appears during `next build`, follow [Debug prerender errors](/docs/app/guides/building#debug-prerender-errors) to enable more detailed stack traces and code frames. You can combine `--debug-prerender` with `--debug-build-paths` to focus on specific routes.

## Static shell and prerendering

- [Runtime data during prerendering](/docs/messages/blocking-prerender-runtime)
- [Uncached data during prerendering](/docs/messages/blocking-prerender-dynamic)
- [URL data in a Client Component outside of Suspense](/docs/messages/blocking-prerender-client-hook)
- [Runtime data in `generateMetadata()`](/docs/messages/blocking-prerender-metadata-runtime)
- [Uncached data in `generateMetadata()`](/docs/messages/blocking-prerender-metadata-dynamic)
- [Runtime data in `generateViewport()`](/docs/messages/blocking-prerender-viewport-runtime)
- [Uncached data in `generateViewport()`](/docs/messages/blocking-prerender-viewport-dynamic)
- [Uncached data outside of Suspense](/docs/messages/blocking-route)

## Unstable values

- [`Math.random()` while prerendering](/docs/messages/blocking-prerender-random)
- [`Math.random()` in a Client Component](/docs/messages/blocking-prerender-random-client)
- [`Date.now()` while prerendering](/docs/messages/blocking-prerender-current-time)
- [`Date.now()` in a Client Component](/docs/messages/blocking-prerender-current-time-client)
- [Crypto APIs while prerendering](/docs/messages/blocking-prerender-crypto)
- [Crypto APIs in a Client Component](/docs/messages/blocking-prerender-crypto-client)

## Non-blocking insights

These insights identify content that is deferred to a later navigation stage without blocking navigation.

- [Dynamic data during prefetching](/docs/messages/instant-link-prefetch-partial)
- [URL data outside of Suspense](/docs/messages/instant-shell-url-data)
- [Unrendered segment](/docs/messages/instant-unrendered-segment)

## Fully static routes

These errors occur when a route uses [`ensureStatic = 'navigation'`](/docs/app/api-reference/file-conventions/route-segment-config/ensureStatic#navigation). The requirement applies even inside `<Suspense>` because the complete server-rendered route must be static.

- [Runtime data on a route that must be fully static](/docs/messages/static-route-runtime)
- [Uncached data on a route that must be fully static](/docs/messages/static-route-dynamic)
- [Runtime data in `generateMetadata()`](/docs/messages/static-metadata-runtime)
- [Uncached data in `generateMetadata()`](/docs/messages/static-metadata-dynamic)
- [Runtime data in `generateViewport()`](/docs/messages/static-viewport-runtime)
- [Uncached data in `generateViewport()`](/docs/messages/static-viewport-dynamic)
- [Missing or incomplete `generateStaticParams()`](/docs/messages/generate-static-params#with-ensurestatic)