Unknown object – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.13

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Briefly, this error occurs when Elasticsearch encounters an object in the request body that it doesn’t recognize. This could be due to a typo, incorrect syntax, or unsupported field in the JSON object. To resolve this issue, you should first verify the syntax and structure of your request body. Make sure that all fields are correctly spelled and supported by your version of Elasticsearch. If the error persists, try to isolate the problematic part by sending smaller parts of your request until you find the unknown object.

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This guide will help you check for common problems that cause the log ” unknown object [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index, blobstore.

Log Context

Log “unknown object [{}]” class name is BlobStoreIndexShardSnapshots.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 FileInfo fileInfo = FileInfo.fromXContent(parser);
 files.put(fileInfo.name(); fileInfo);
 } else if (token == XContentParser.Token.START_OBJECT) {
 if (ParseFields.SNAPSHOTS.match(currentFieldName; parser.getDeprecationHandler()) == false) {
 throw new ElasticsearchParseException("unknown object [{}]"; currentFieldName);
 while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
 XContentParserUtils.ensureExpectedToken(XContentParser.Token.FIELD_NAME; token; parser);
 String snapshot = parser.currentName();
 XContentParserUtils.ensureExpectedToken(XContentParser.Token.START_OBJECT; parser.nextToken(); parser);


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