I'm using Office 2013 with the Upload Center uploading files to a SharePoint.
I have one file stuck in the Center with the state "Path not found":

That is because while the was upload I moved/deleted it --> inconsistent state.
However I can't click on Resolve > Discard Changes:
"The action can't be completed because the file is open."
I also can't Resolve > Open to Resolve:
"File does not exist"*
I can't Resolve > Save a copy:
"File does not exist"
How do I tell Upload Center to forget all current uploads?