The code

``` javascript
class Comp extends React.Component {
  componentWillMount() {
    setTimeout(() => {
      this.setState({});
    });
  }

  render() {
    return <div onClick={() => {}} />;
  }
}

ReactDOMServer.renderToString(<Comp />);
```

produces errors:

> Warning: React can't find the root component node for data-reactid value `.0`. If you're seeing this message, it probably means that you've loaded two copies of React on the page. At this time, only a single copy of React can be loaded at a time.
> 
> Uncaught TypeError: Cannot read property 'firstChild' of undefined

But if I remove `onClick` handler the errors go away...

See demo: http://codepen.io/dened/pen/YyByYr

);
        }
      }
    }
    return instanceOrElement;
  },
  performInitialMountWithErrorHandling: function(
    renderedElement,
    hostParent,
    hostContainerInfo,
    transaction,
    context
  ) {
    var markup;
    var checkpoint = transaction.checkpoint();
    try {
      markup = this.performInitialMount(renderedElement, hostParent, hostContainerInfo, transaction, context);
    } catch (e) {
      
      transaction.rollback(checkpoint);
      this._instance.unstable_handleError(e);
      if (this._pendingStateQueue) {
        this._instance.state = this._processPendingState(this._instance.props, this._instance.context);
      }
      checkpoint = transaction.checkpoint();
      this._renderedComponent.unmountComponent(true);
      transaction.rollback(checkpoint);
      
      
      markup = this.performInitialMount(renderedElement, hostParent, hostContainerInfo, transaction, context);