I am having a problem with my screen saver changing on its own on my imac 27.5. I had the same problem soon after I got it and I had it in at Apple Park City and the guy made a change in the system somewhere and it fixed it. Since then, I had a problem with it and had it in for warranty work and it must have gone back to the original setting. I will set the screen saver to a folder with pics, but before long it changes to another location on its own. The box "crop slides to fill screen" will also get checked on its own as well. I was in at Apple the other day for a projects class and the guy had no answer for me. He wasn't sure how to keep it from happening. Can anyone help?