I too have encountered this same problem over the past few months with locally installed Microsoft Office 365 on multiple PCs while running previous and the latest (1909) versions of Microsoft Windows 10 Pro. I have unchecked anything relating to Office 365 on Ccleaner, but without any effect on resolving this problem. I have been using Ccleaner forever, and this problem only started occurring with the relatively recent versions of Ccleaner. Very frustrating to have to repair (reinstall) Office 365 so many times.