Why ChunkLoadError Happens After React/Next.js Deployments and How to Fix It

React and Next.js applications split JavaScript into smaller files called chunks, which browsers load on demand rather than all at once. When a new version is deployed and old chunk files are removed from the server, users who still have the previous version open in their browser encounter a ChunkLoadError because their runtime requests files that no longer exist. Simply refreshing the page resolves the error temporarily by loading the new version, but it does not address the underlying deployment architecture problem. The root cause is a version mismatch between the JavaScript runtime running in the user's browser and the assets now available on the server. Proper solutions include keeping old assets available during transitions, using immutable versioned files, and adopting atomic or rolling deployment strategies to prevent serving broken states to active users.