It looks like last two updates fixed the problem for me. No idea if it was intended, but thank you for that.

I'm having same problem lately. It seems Opera is having some closing issues while your computer or Opera itself is busy. I'll report it after I've done more testing. I'll try to determine what's causing it and report it then.

Only fix I found so far is to restart my computer every time it happens.

And what you can do is be careful when closing Opera: let all pages fully load before you close them, close all of your tabs, wait several seconds and then close Opera, wait at least 1 min before opening Opera again. Unfortunately this doesn't help every time so there's a lot of restarts.

I've tried using another browser and it's just too hard to get used to them. I've decided to stay with Opera and keep restarting my computer.

I can see there is a primary problem to be diagnosed in the first place.

1. "having trouble with loading sites/settings/history", 2) "I have large amount of tabs opened for a long time and they need to be loaded back (white screen) to be seen again" whatever that means.

It can help. Antivirus software may hold files locked for some time after closing them (scanning for malware);...

Thank you for your input guys.

Afer some testing I've managed to recreate this error by opening video on youtube, switching to unloaded part and closing Opera right away. Doing this leaves two Opera processes opened for indefinite time: opera.exe and opera_crasherror.exe. However it doesn't occur every time.

Closing Opera right after an site is starting to open will cause those two processes to stay open, however for only short amount of time, up to 45 seconds, depending on the size and the elements of the site.

So my conclusion is that while closing, Opera is still trying to save site information and if it's too large or lasts for too long it just stays there without closing last two processes. Which causes error upon next Opera launch.

It happens because Opera may need a while after have been closed to update its files, so if you reopen it just after then the files will still being used and the message error shows up.

Alright, thank you for info. I'll keep an eye on it and post back if issue is caused by something else too.
But is there any way to start Opera again if this error appears, other than restarting computer?

Do you reopen Opera just after have closed it? When you do it, the issue you are reporting may happens.

That's correct. When I try to reopen it this issue appears. However it doesn't happen everytime and it sometimes happen even several minutes after I closed it (while it was working fine and I wasn't trying to reopen it in the meanwhile).

Hello donq, thank you for answering. Yes I'm using Avast antivirus. Do you think it's causing it?

Hello,

I know this is known problem and I tried to find solution in previous posts but without success, so I'm asking you for tips and help.

This problem occurs when I close my Opera while it's having trouble with loading sites/settings/history or if I have large amount of tabs opened for a long time and they need to be loaded back (white screen) to be seen again. Closing Opera during those operations will cause next Opera launch to fail with following message: "Can't open user profile directory, because you lack sufficient privileges. You might want to contact the administrator of this machine."

In my task manager are visible 3 opera.exe entries and 2 of them can be "killed" while third one remains no matter what.

I've made few attempts to fix this problem by giving full permissions to my user/System/administrator (even I'm the administrator) on all Opera folders/files in Program Files and AppData, together with deleting my whole browsing history in safe mode and complete Opera reinstallation. However nothing prevented this problem from future occurring.

Only temporary fix I found so far was to restart my computer every time it happens. Upon new Windows start everything works in order until previously described situation happens.

I'm currently using Opera Stable 41.0.2353.46 version on my Windows 7 Ultimate.

I would be really grateful if anyone could help me with this problem.