Thank you for a reply that actually feels like it wants to help. I appreciate it.
Version: 41.0.2353.56
Update stream: Stable
System: Windows 10 64-bit (WoW64)
Reiterating this all started around a September update.
If I think back, I first noticed it deleting settings. I noticed that flash wasn't working and that I needed to re-enable "plug-ins." It defaults to "Click to play" despite the setting I want saying it is "(recommended)." This happens a few times a week? I honestly don't know exactly how much because HTML5 is a thing now, so running into flash isn't as common as it used to be. (Also on that note, click to play doesn't actually work.)
I also noticed it would turn off the VNP setting, and sometimes it would turn on the ad blocker, which I do not want to use. It probably changed other stuff, but as it didn't cause inconvenience, I didn't notice.
My browser also started to freeze up. The scrollbar would randomly disappear. The screen would sometimes go all black. Sometimes when I would open a new tab the tab would be blank and I need to clone it to see anything else.
I use extensions, but opera deleted them all. This is what set me off to ask for help, although I admit I came of rude. This on top of the page freezing and settings issues.... I was frustrated, and the other users dismissiveness just set me off even further. I am sorry for that.
I have "Synchronization: You're currently signed in [...]" and "Background sync: Allow recently closed sites to finish sending and receiving data (recommended)" and am not aware of any other sync settings so... yes? I think i have sync enabled.
Today I woke up to find all of my bookmarks have been deleted as well.
I use Avast free.
Windows is working fine and I am on 1511. (I didn't like the Anniversary update so I rolled back. I don't believe these problems are related, though.)
Also my Opera menu bar just went red... so I guess there is an update. So I will probably click to install that later tonight unless you think I shouldn't.
Again, I am sorry I am so abrasive, but when a browser you love and trust starts to delete things, and just previously you were looking for a way to back up your data, only to find it doesn't have the option to do that natively.... It is pretty irritating. If I had the option to back everything up, I would have just done a clean reinstall.... And even if that didn't work... I wouldn't be in the position I am now having lost everything.