So I've got a Document under an approval workflow, but I'd rather not let the users edit the document while the workflow is active to keep consistency on everyone's approval (it's multi-step). I've toyed with a few possibilities:
1) Checking out the document, but then other users had difficulties setting approval and the workflow malfunctioned
2) I can set up a document in Word or Excel 2010/2013 not to be edited by Word and Excel settings, but PDF's are in this library as well.
3) I know custom development could probably be done, but seeing as this is SharePoint online and any solutions likely won't fit in a sandbox, I'm hoping for a better way. Also the capabilities aren't really in house to maintain code, so I'm hoping to keep it out of the box or SharePoint designer. Third party tools are welcome too as long as they can work in SharePoint online.