Expected array for ” + field + ” – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

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

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.

This guide will help you check for common problems that cause the log ” expected array for ” + field + ” ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repositories.

Log Context

Log “expected array for [” + field + “]”classname  is RepositoryData.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

if (metaGenerations.isEmpty() == false) {
 indexMetaLookup.put(snapshotId; metaGenerations);
 } else {
 throw new ElasticsearchParseException("expected array for [" + field + "]");
 } else if (INDICES.equals(field)) {
 if (parser.nextToken() != XContentParser.Token.START_OBJECT) {
 throw new ElasticsearchParseException("start object expected [indices]");


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