Could not lock IndexWriter – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

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Briefly, this error occurs when Elasticsearch is unable to obtain a lock on the IndexWriter, which is needed to prevent concurrent modifications to the index. This could be due to multiple instances of Elasticsearch running on the same directory or a previous instance not releasing the lock properly. To resolve this issue, ensure only one instance of Elasticsearch is running on the directory. If the problem persists, manually remove the lock file from the index directory. However, be cautious as this could lead to data corruption if an instance is still using the index.

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This guide will help you check for common problems that cause the log ” could not lock IndexWriter ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index.

Log Context

Log “could not lock IndexWriter” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

    private IndexWriter createWriter() throws IOException {
        try {
            final IndexWriterConfig iwc = getIndexWriterConfig();
            return createWriter(; iwc);
        } catch (LockObtainFailedException ex) {
            logger.warn("could not lock IndexWriter"; ex);
            throw ex;

    // pkg-private for testing


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