Hello everybody.I've managed to solve the problem. Apparently the problem were in the .json file that I had. I experiment going to the other linux (mint) machine that I have and getting a new *.json file do the same as usual (bookmarks>Show all bookmarks>Import and Backup>restore>chose file>myBookmarks.json) and it worked without a flaw. I wan to to thank to all the time and patience you all have: many many thanks to all!!!
See you more soon than later I hope; Hugs to all
