I was trying to develop a workflow using Visual Studio 2012 for SharePoint 2013. When I was trying to publish the workflow i was getting the following exception:
Microsoft.Workflow.Client.ActivityValidationException: Workflow XAML failed validation due to the following errors:
Cannot set unknown member 'LookupSPListItem.ItemId'.
HTTP headers received from the server………….
Then after googling i had found the hint in the Microsoft Forum.
Basically you need to re-register the workflow using a Powershell command like below. I think when any Workflow Manager or SharePoint update is installed in the server, these two components get out of sync and re-running the registration will sync both again.
Register-SPWorkflowService -SPSite "SiteURL" -WorkflowHostUri 'WorkflowHostURL' -Force
Remember to mention Force switch. After the command, restart the Visual Studio or SharePoint Designer and hopefully the issue will be fixed.