title: LeaseAlreadyPresent Error in Azure Data Factory V2
body: <p>I am getting the following error in a pipeline that has <strong>Copy activity with Rest API</strong> as source and <strong>Azure Data Lake Storage Gen 2</strong> as Sink.</p>
  <blockquote>
  <p>&quot;message&quot;: &quot;Failure happened on 'Sink' side. ErrorCode=AdlsGen2OperationFailed,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=ADLS Gen2 operation failed for: Operation returned an invalid status code 'Conflict'. Account: '{Storage Account Name}'. FileSystem: '{Container Name}'. Path: 'foodics_v2/Burgerizzr/transactional/_567a2g7a/2018-02-09/raw/inventory-transactions.json'. ErrorCode: 'LeaseAlreadyPresent'. Message: 'There is already a lease present.'. RequestId: 'd27f1a3d-d01f-0003-28fb-400303000000'..,Source=Microsoft.DataTransfer.ClientLibrary,''Type=Microsoft.Azure.Storage.Data.Models.ErrorSchemaException,Message=Operation returned an invalid status code 'Conflict',Source=Microsoft.DataTransfer.ClientLibrary,'&quot;,</p>
  </blockquote>
  <p>The pipeline runs in a for loop with <code>Batch size = 5</code>. When I make it sequential, the error goes away, but I need to run it in parallel.</p>