I have had to delete Ccleaner. I bought 2 applications of it.
First, the Ccleaner Pro, then Ccleaner technician edition.
Despite unchecking the boxes for deletion of dll, I find that Office 2016 and Office 2019 will not start after use of Ccleaner.
I have to go on Win 10 control panel, check the repair function for Office and do the full, online download of Office again.
The quick repair doesn't fix it.
I reckon Ccleaner is deleting a required dll. I haven't found anything to stop it doing this.