Slide Master Layouts - Tells me they are being used but no slides using them? Jan 13, 2016 By Alan Maguire In my storyline file there are slide layouts and masters that I want to get rid of but storyline is telling me they are being use by slides. They are not being used by any visible slides. I have even gone in there and assigned all slides to 1 layout to try and free them up but no good. Does the file need a clean up? Are there hidden slides I cannot see? Can anyone help with this?