React
React recovered from a concurrent rendering error by switching to sync render
There was an error during concurrent rendering but React was able to recover by instead synchronously rendering the entire root.
React encountered a concurrent rendering problem and fell back to synchronously rendering the full root to recover.
Observed message
There was an error during concurrent rendering but React was able to recover by instead synchronously rendering the entire root.
Why it happens
- A rendering path is not behaving safely under concurrent rendering.
- Side effects or unstable data during render caused React to abandon the concurrent attempt.
- A Suspense or async boundary exposed a rendering path that only fails under concurrency.
How to fix it
- Reproduce the issue in development and inspect the underlying rendering error.
- Review render logic for side effects, unstable values, and assumptions that only work in synchronous rendering.
- Check nearby Suspense and async boundaries to find the component that triggered the fallback.
