---
title: Webpack Build Worker automatic opt-out
---

## Webpack Build Worker Opt-out

#### Why This Error Occurred

The Next.js config contains custom webpack configuration, as a result, the webpack build worker optimization was disabled.

The webpack build worker optimization helps alleviate memory stress during builds and reduce out-of-memory errors although some custom configurations may not be compatible.

#### Possible Ways to Fix It

You can force enable the option by setting &#x60;config.experimental.webpackBuildWorker: true&#x60; in the config.
