What operating system are we talking about here? (Windows, Mac, Android?) : Windos 10
What had you been doing when you noticed that the folder had gone missing? Looking for a date in one of its documents
Where was the folder located? In my Documents
Why do you think that CCleaner has deleted a folder? I used CCleaner a few days before
What had you run in CCleaner? (Health Check, Custom Clean, Registry Cleaner, something else?) I thing it's called Health Check