With the new 2013 workflows there are a few scenarios that can cause issues which may not be obvious to those coming from 2010. One such scenario is configuring list items to have Create and Edit access set to Create items and edit items that were created by the user and have a user who did not create the item initiate a 2013 workflow. By default, this will result in the workflow failing due to unauthorised access exceptions.
Lets walk through the scenario in more detail.
Start with creating a new custom list and then in SharePoint Designer, publish a simple List workflow to it.
As you can see, a very simple workflow 🙂
Configure the list to allow users to only edit items that they created.