Summary:Why am I receiving the following error when trying to publish a workflow? "Server was unable to process request. ---> The file http://servername/Workflows/NintexWorkflow/foldername/filename.xoml is checked out or locked for editing by domain\username."
Product:All Workflow for SharePoint on-premises
The file has somehow been locked. Open your site in SharePoint Designer then drill down to the folder/.xoml file path shown in the error. Right-click on the .xoml file(s) and discard checkout.