Why is App Step greyed out in SharePoint Designer

Question

Office 365 - SharePoint

I have what appears, on the face of it, to be a pretty straightforward List Workflow.

Each document added to the Document Library (List) has two custom columns of type Choice - let's call them User Status and Workflow Status. When the user changes the User Status to value 1 - Send First Email, the Workflow sends an email to the author and changes the Workflow Status to value 1. When the user changes the User Status to value 2 - Send Second Email, the Workflow sends a second email to the author and changes the Workflow Status to value 2. When the user changes the User Status to value 3 - Move Document, the Workflow moves the document to a different Document Library and changes the Workflow Status to value 3.

Over the course of the past month, the Workflow has performed extremely badly. Sometimes (about 65% of the time) it runs correctly to completion. Sometimes it will send the First Email and then do nothing further. Sometimes it will send the Second Email and do nothing further. In both these instances the status of the Workflow remains "Started", with no apparent error messages.

My client is getting extremely annoyed about this (not surprisingly). I have lodged a Support Request with Microsoft and they are trying to get to the bottom of it, but in the meantime I'm trying all sorts of things to get it to work.

So, two questions.

1. Does this scenario strike a chord with anyone?
2. In my investigations I've come across something called App Step, which changes (as I understand it) the permission level for the workflow step. However, I seem to be unable to add an App Step to my Workflow because it's greyed out, so I cannot test to see if it solves the problem.

Any help would be greatly appreciated.

Thanks

Edward

Answer 1

1. Must be a site owner.
2. Must publish the workflow.
3. Must turn on the Site Feature "Workflow can use app permissions" in the Site Settings > Manage site features.