I and into a situation this week that I have never encountered. Some of my workflows were in a waiting state and when I opened one to check for an error, this is what I saw:
I had some issues with the transition to Office 365 (from Live ID) and I had to disable my user and recreate myself. This caused all of the workflows that were owned by the “old me” to stop working.
So, make sure that you check the ownership of your workflows and verify that the state of the owner of the workflow is not disabled.
This Advanced Find does that query:
By the way, do not be scared of that first part. When you select processes, it adds all of those filters. All you need to do is add the Owning User (User) related entity filter.