vercel/next.js · error

Failed to update prerender cache for

Error message

Failed to update prerender cache for

What it means

Warning logged in IncrementalCache.set after the configured cacheHandler.set(...) call threw while persisting a prerender entry for the given pathname. The catch block deliberately swallows the handler failure and continues — a failed cache write degrades freshness but must not break rendering — so the operator only gets this console.warn naming the pathname and the underlying error.

Source

Thrown at packages/next/src/server/lib/incremental-cache/index.ts:790

      !ctx.isImplicitBuildTimeCache
    ) {
      const warningText = `Failed to set Next.js data cache for ${ctx.fetchUrl || pathname}, items over 2MB can not be cached (${itemSize} bytes)`

      if (this.dev) {
        throw new Error(warningText)
      }
      console.warn(warningText)
      return
    }

    try {
      if (!ctx.fetchCache && ctx.cacheControl) {
        this.cacheControls.set(toRoute(pathname), ctx.cacheControl)
      }

      await this.cacheHandler?.set(pathname, data, ctx)
    } catch (error) {
      console.warn('Failed to update prerender cache for', pathname, error)
    }
  }
}

View on GitHub (pinned to 43273a1d21)

Solutions

1. Check filesystem permissions and available disk space for the .next cache directory.
2. Verify the cache handler configuration and connectivity if using a custom external cache.

When it happens

Trigger: Thrown at packages/next/src/server/lib/incremental-cache/index.ts:785 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@43273a1d21 (2026-08-19). Data as JSON: /api/errors/b97936f96f1feef5. Report an issue: GitHub.