Fatal error in thread ; exiting – How to solve related issues

Opster Team

Jan-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you run Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many errors.

Briefly, this error indicates a serious issue with the Elasticsearch server. It can be caused by a variety of factors, such as hardware failure, software bugs, or configuration issues. To resolve this issue, you can try restarting the Elasticsearch service, checking the server logs for any error messages or stack traces, and checking the hardware and software components for any issues. It may also be helpful to consult the Elasticsearch documentation or seek assistance from Elasticsearch support.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them. Take a self-guided product tour to see for yourself (no registration required).

This guide will help you check for common problems that cause the log ” Fatal error in thread ; exiting ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: bootstrap, handler and thread.

Log Context

Log “Fatal error in thread [{}]; exiting” classname is ElasticsearchUncaughtExceptionHandler.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

     static boolean isFatalUncaught(Throwable e) {
        return e instanceof Error;

    void onFatalUncaught(final String threadName; final Throwable t) {
        logger.error(() -> new ParameterizedMessage("fatal error in thread [{}]; exiting"; threadName); t);

    void onNonFatalUncaught(final String threadName; final Throwable t) {
        logger.warn(() -> new ParameterizedMessage("uncaught exception in thread [{}]"; threadName); t);


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