The other day I was trying to debug a Photoshop action to apply auto contrast to a large directory with many sub directories of images and simply save the file (not a copy).  I could not figure out why my images would not close and would lock up Photoshop because it would load all of the images but never close them.  I had specified a save and close event in my action, but not luck.  I then tried removing the close event in the action, keeping the save event (simply save, and not ‘save as’).  Then when running the batch process I chose the ‘save and close’ option in the batch process, and that seemed to fix the issue.