As it stands, when you use Sandboxie to open Opera, all changes made during the session will be lost on closure and Opera reverts back to the previous state. This problem is a very messy one to solve and often with no result. I am giving here the solution so that Opera users can easily fix the problem.
Using Opera as default browser with Sandboxie to open it. Do the following - Bring up the SBxie Control Panel - right click the taskbar icon. Then follow - Sandbox>Default box>Settings>Resource access>File access>Direct access
Using Edit/Add copy and paste each one of the following settings into the panel separately one after the other :-
Then click Apply/OK. When entering the settings are visible in the panel, but when Apply is clicked, they disappear. No problem, this is OK.
Now, when Opera is shut down all changes made during the session will be saved and on reopening with SBxie the changes will still show
Are you saying that all the settings save correct except for those two files? Seems like you'd want to whitelist/add (however you do it for sandboxie) these 2 paths:
"%AppData%\Opera Software\Opera Stable"
"%LocalAppData%\Opera Software\Opera Stable"
to cover all the preference files for that particular Opera.
Or, are you saying that Opera tries to create a Bookmarks and Thumbnails folder in "%AppData%\Opera Software" next to "Opera Stable" and sandboxie doesn't all that by default?
My post is not a discussion, it is a solution.
Sandboxie was not saving bookmarks on Opera closure. By inserting the fixes I give in my post into the sandboxie settings, this problem was solved and on browser closure now, all bookmarks saved during the sandbox session are now shown in the unsandboxed Opera after closure..