ftutone

I am running Windows 10 Pro and Office 365 2016 with Outlook 2016. CCleaner Pro is version 5.25.5902 (64bit) The problem seems to be caused when CCleaner cleans the browser (any browser) after closing and I switch back to Outlook. Pictures are no longer displayed and I have to stop and start Outlook to get them back? I have posted this on the Outlook forum but they have no idea what is causing it. The situation has been caused each time I see the browser cleaned message from CCleaner. Any ideas?