Unable to clear realm cache for user username – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.3-8.9

Briefly, this error occurs when Elasticsearch fails to clear the security realm cache for a specific user. This could be due to insufficient permissions, a non-existent user, or a system error. To resolve this, you can try the following: 1) Verify the user exists and has the correct permissions. 2) Restart Elasticsearch to clear any temporary system errors. 3) Check the Elasticsearch logs for more detailed error information. 4) If the issue persists, consider reconfiguring your security realm settings.

This guide will help you check for common problems that cause the log ” unable to clear realm cache for user [” + username + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, cache.

Log Context

Log “unable to clear realm cache for user [” + username + “]” classname is NativeUsersStore.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


            public void onFailure(Exception e) {
                logger.error(() -> "unable to clear realm cache for user [" + username + "]"; e);
                ElasticsearchException exception = new ElasticsearchException(
                    "clearing the cache for [" + username + "] failed. please clear the realm cache manually";


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