@leocg You should use the sq database to open the "history" file, which records your downloads or history and preferences. Normally, my "history" file is 9MB, but now it is only 190KB (which means it deleted the "history" file, thus creating a new "history," and the data stored in the file is gone). The browser automatically deletes the history without deleting information other than the history.
(This has happened before, but it has never happened with other browsers on my computer, including Chrome and Edge.)

@leocg I have explained clearly that all the data in the history table disappeared, so I think opera deleted my "history" file. I am using Opera One.

(The problem cannot be reproduced using the browser's built-in deletion function, and my cookies are all normal)

Just yesterday, I don't know why Opera only deleted my "history". Other cache and bookmark files are normal.I didn't use the browser to delete the history, and the download history disappeared as well. Does anyone know where the history backup file is located?

Recently I found that Easy Files will not pop up when uploading pictures on some websites, or even choose files.Can't even select files. The browser version number is 75.0.3969.171. This is a recent problem. Easy Files can pop up normally before.（Not all websites are unavailable）