Profile uid does not contain any underscore character – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 8.2-8.9

Briefly, this error occurs when the profile UID you’re using in Elasticsearch doesn’t contain an underscore character. Elasticsearch uses underscores in UIDs for specific purposes, and if it’s missing, it can cause issues. To resolve this, you can modify the UID to include an underscore. Alternatively, if the underscore isn’t necessary for your use case, you can adjust your Elasticsearch settings or code to accept UIDs without underscores. Always ensure that your UIDs follow the correct format to avoid such errors.

This guide will help you check for common problems that cause the log ” profile uid [{}] does not contain any underscore character ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Log Context

Log “profile uid [{}] does not contain any underscore character” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 void maybeIncrementDifferentiatorAndCreateNewProfile(Subject subject; ProfileDocument profileDocument; ActionListener listener)
 throws IOException {
 final String uid = profileDocument.uid();
 final int index = uid.lastIndexOf("_");
 if (index == -1) {
 listener.onFailure(new ElasticsearchException("profile uid [{}] does not contain any underscore character"; uid));
 final String baseUid = uid.substring(0; index);
 final String differentiatorString = uid.substring(index + 1);
 if (differentiatorString.isBlank()) {