My personalised Homepage (with many quick dial buttons) doesn't show up since about two weeks, and I am not able to restore it! With that other features like the to-read-sites, ad-blocker, and ghostery are lost as well. Please, can anybody give me an advice how to restore it?

@yanta
And the switch to earlier versions and back to the actual one did work as well now!
Thank you all for helping me so much!!

Great, that's helpful!
Thanks a lot for the quick reply!

When I save an Opera page (for example in my folder "philosophy"), then there I not only have this file but additionally a extra folder (as well in the folder "philosophy") with the same name (with "files" at the end). This is very annoying. What can I do to prevent that?

@yanta
And the switch to earlier versions and back to the actual one did work as well now!
Thank you all for helping me so much!!

@yanta
Hurra!! I've got my To-Read sites back - with all the sites I've filed there!!!

Thank you yanta for these hints, but it seems there is really something odd:
The link to the To-Read sites is what I meant - I installed it but can't see it anywhere...
And I tried to install a previous version of Opera - I downloaded it, but when I clicked on "execute", nothing happens...

How can I do that?
I am going to bed now, so I am looking forward to your answer tomorrow morning...

@leocg
SyncToy is for the data only, but I used Opera-safeguarding (Opera-Sicherung in German) for the same reason, so I have a folder with Opera-backups, the last one dated 2016.
Might this be useful?

@yanta
I just had a look at the extensions and realised that now I only have adblocker, and on the list of Opera's extensions there is no ghostery nor the to-read-sites!!??
Might this be the problem? And is there a possibility to go back to a previous version (just for a short time so that I have access to my to-read-sites and store them?
And what about the option to set back Opera to the original state?

I used SyncToy to store my Laptop-data on my very old PC, which is not working any more. The last time I did it, was 2016. Might there be an option (without being able to use my old PC)?

Then I have definitely Chromium.
As for the previous version: I always try to be updated, so the last update was from the directly previous version.