Thank you very much again. @burnout426 said in Recover bookmarks:

The more bookmarks you have, the slower Opera will get and the more work Sync will have to do.

And if I don't synchronized the bookmarks can Opera also get slower? I mean if you have many bookmarks (in my case they are now almost 500)

Thank you very much for yout very useful help!! Now I have resolved the problem with the synchronization, at least I have deleted the old ones in the Sync Data folder and I have added my new ones from my saved bookmarks html-document. Now I have logged in and synchronized my bookmarks and I see that my new bookmars appear in the bookmarks' folder at https://www.sync.opera.com, perhaps not all of them so far, but I see they are appearing more and more and probably it is completed in some minutes,

What I didn't really understand is if I must delete the Sync Data folder again even if everything looks right when I am logged in the synchronized browser.

And one question more: I have almost 500 bookmarks. I wonder if the computer can be significantly slower when you have a lot of bookmarks? or does this factor not influence the speed of the computer?

I had rebuilt manually my bookmarks from my old bookmarks from 2019 adding new ones, it took me a long time, but when I finished I thought it would be a good idea to synchronised them in order not to lose them in the future. But when I press synchronisation all the changes I have done disappeared. I am so frustratred now. How can I get my new bookmarks back? It has only taken some minutes from the unfortunate synchronisation.

@burnout426 Thank you. I think you are right, I have tried seraching previous versions in the Opera user files and I found nothing. I think I give up.

I have reinstalled Windows 10 from scratch and now I have lost my bookmarks. I have only my old bookmarks from 2019 saved in my Opera account, but after that year I have used Opera without having synchronised bookmarks and without log in. But the computer is the same. I wonder if there is some way to recover my most recent bookmarkers. There are many. Maybe with Recuva??

During the last months my Opera browser has been attacked by malware or cryptomines and the result is that CPU is very burdened (often near 100%) and the RAM-memory runs out quite quickly, after some hour of computer use or earlier, if I stream something. What can I do to restore the browser? Antivirus found nothing, only Malwarebytes found PUP.Optionals from a VPN I had acquired. Now I have these PUPs in the quarantine and use in the meantime another browser. I also wonder if it can be risky to export my favorite sites from Opera to another browse in the present moment. I am afraid that the new browser (probably Firefox) will also be infected by these PUPs.