Unable to clean unused element – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.11-8.9

Briefly, this error occurs when Elasticsearch tries to clean up unused elements, such as old indices or cache, but fails due to insufficient permissions, lack of disk space, or a locked file. To resolve this issue, you can try the following: 1) Check and adjust the permissions of the Elasticsearch directories. 2) Free up disk space or increase the disk capacity. 3) Identify and unlock the locked files that Elasticsearch is trying to clean. Always ensure to back up your data before performing these operations to prevent data loss.

This guide will help you check for common problems that cause the log ” Unable to clean unused element ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: azure, repositories, repository-azure.

Log Context

Log “Unable to clean unused element” classname is CancellableRateLimitedFluxIterator.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

    private void cleanElement(T element) {
        try {
        } catch (Exception e) {
            logger.warn("Unable to clean unused element"; e);

    private void cancelSubscription() {
        Subscription previousSubscription = subscription.getAndSet(CANCELLED_SUBSCRIPTION);


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