Failed to load kuromoji user dictionary – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch fails to load the ‘kuromoji’ user dictionary, which is a Japanese language analysis plugin. This could be due to a missing or incorrectly configured dictionary file. To resolve this issue, ensure that the dictionary file is present in the specified path and correctly formatted. Also, check the Elasticsearch configuration to ensure it’s correctly pointing to the dictionary file. If the problem persists, consider reinstalling the kuromoji plugin or upgrading Elasticsearch to the latest version.

This guide will help you check for common problems that cause the log ” failed to load kuromoji user dictionary ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, plugins, analysis.

Log Context

Log “failed to load kuromoji user dictionary” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 for (String line : ruleList) {
 return StringReader(sb.toString()));
 } catch (IOException e) {
 throw new ElasticsearchException("failed to load kuromoji user dictionary"; e);
 }  public static JapaneseTokenizer.Mode getMode(Settings settings) {
 JapaneseTokenizer.Mode mode = JapaneseTokenizer.DEFAULT_MODE;


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