I've tried both set field value and update item. When I upload a new document, I have an action to rename the file to a standard we want to use. When I click to save the metadata window on the typical file uploaded, I get this message "The file Shared Documents/Sample2.pdf-17.pdf has been modified by crenshaw on 12 Mar 2015 15:09:14 -0500." I select cancel and the file is uploaded and the name is changed (no workflow error). I want to avoid the error message when they're saving the file. I tired Commit changes as the first action.
It may be because the workflow is executing as soon as the document is uploaded. When you are entering the metadata, the workflow is already in progress. Try pause at the start of the workflow or trigger the workflow based on the metadata of the document.