I am using opera 39.0 in french
Last morming I start the browser and the start page who appeared was 1 year old +, and all my regular daily bookmarks had disappeared , replaced by the old one ( a year old + ) !!
The start page? You mean the speed dial? If you go into your bookmarks manager
(Ctrl + Shift + B)and look at 'Other Speed Dials' what do you see in there?