Invalid Index Name [-YYYY.MM], Must Not Start With '_', '-', Or '+'"

Recurrent Error message in Windows Applications logs event with ElasticSearch since upgrade to LTS 2022.4.1: ElasticSearch: Bulk item failed: index:-2022.07 result: type:logEvent error:Type: invalid_index_name_exception Reason: "Invalid index name [-2022.07], must not start with '_', '-', or '+'" .

  1. Check the dbo.settings , make sure Value column is not empty for tenants.
  • SELECT * FROM [UiPath].[dbo].[Settings] where name='LoggingIndex'

  1. Error may appear as well in case when robotElasticBuffer is configured in rules for BusinessException.* and *


<logger name="BusinessException.*" minlevel="Info" writeTo="businessExceptionEventLog,robotElasticBuffer" final="true" />

<logger name="Robot.*" ruleName="primaryRobotLogsTarget" final="true" writeTo="robotElasticBuffer" />

<logger name="*" minlevel="Info" writeTo="eventLog,robotElasticBuffer " />


  1. Remove robotElasticBuffer from <logger name="BusinessException.*"/> and <logger name="*"/>, leave only for <logger name="Robot.*"/>
  2. Perform an IIS reset .