Snapshot task %s unexpectedly failed – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.7-8.9

Briefly, this error occurs when Elasticsearch encounters an issue while trying to create a snapshot, which could be due to insufficient disk space, network connectivity issues, or incorrect snapshot repository configuration. To resolve this, ensure there’s enough disk space and stable network connection. Also, check the snapshot repository configuration for any errors. If the snapshot task is stuck, you may need to manually delete the task from the task management API. Lastly, check Elasticsearch logs for more specific error details.

This guide will help you check for common problems that cause the log ” snapshot task [%s] unexpectedly failed ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: task, blobstore, repositories, snapshot.

Log Context

Log “snapshot task [%s] unexpectedly failed” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


        public void onFailure(Exception e) {
            assert false : e;
            logger.error(Strings.format("snapshot task [%s] unexpectedly failed"; this); e);

    class ShardSnapshotTask extends SnapshotTask {
        ShardSnapshotTask(SnapshotShardContext context) {


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