Many times while running CCleaner it would crash. I thought the problem was because I would start LoL with it right when I start my laptop, but turns out I was minimizing the window in the middle of scanning or cleaning. I noticed it was the problem when I minimized it to look at my emails. The scan time or clean time has to be at least 8 seconds long it won't happen. I've noticed everytime that I did minimize in the middle CCleaner it crashed. Although I believe only the window closes because if it crashes during cleaning and you run CCleaner again it will be cleaned & have virtually nothing will show up in the scan. Hope this helps if you don't know why CCleaner crashed.