Today I ran into a simple but time consuming problem where a basic list approval workflow created in SharePoint Designer enters a "Stopped" status when a non administrative user starts the workflow. No error message appeared in the Workflow History either - it just stopped.
What happens is that the workflow is initiated when a new item is created in the list. Very simply the workflow creates a task for a team and emails the users that are stored in a SharePoint Group. The creation of the workflow task and email sending to a SharePoint Group causes the workflow to enter a Stopped state.
After hitting my head on the table and checking the workflow a couple of times, it is important to note that due to the fact I'm sending emails to a SharePoint Group, I need to activate the have a Group Setting to allow Everyone to view membershiop of this group.
Fixing this is simple, go to your Site Settings | People and Groups, select the group you're using. On the Settings menu option for the Group click the Group Settings option and toggle the membership button to Everyone.
You're good to go!