@burnout426 Thanks for that! I followed your advice (and leocg's) and found the sessions folder. There were Three session... and Two tabs.... files. I closed the extra windows and One session.... file was removed by Opera leaving 2 each of session... and tabs,,,, files.
I then created and deleted tabs and watched the files change size etc. One pair of files remained static so I deleted them.
Then I restarted Windows and Opera started (automatically) with Only One window. YAY! I now hope this fix is permanent but only time will tell.

Thank You both for your help ️️

I tried Americas, Europe and Asia - none of them work. From Western Australia.

Is it me or is this a general situation?

@burnout426 Thanks for that! I followed your advice (and leocg's) and found the sessions folder. There were Three session... and Two tabs.... files. I closed the extra windows and One session.... file was removed by Opera leaving 2 each of session... and tabs,,,, files.
I then created and deleted tabs and watched the files change size etc. One pair of files remained static so I deleted them.
Then I restarted Windows and Opera started (automatically) with Only One window. YAY! I now hope this fix is permanent but only time will tell.

Thank You both for your help ️️

@leocg Sorry I would love to try this but How exactly? I've looked in AppData and found the Opera folder but I no clue how to do what you're suggesting.

Thanks for the suggestion though ️

@leocg I only ever open both my browsers automatically each morning when I switch on. I also never "kill" them as I always shutdown with them on screen. I do remember "killing" Opera once and I lost all my usual tabs so I haven't done that again....
There's an outstanding update - I'll do that and see if I get three windows again! But I have to wait till my 10 minutes to post this response....

@leocg I haven't a clue! AFAIK I downloaded Opera and installed it. When I look in Task Manager it just says Opera Internet Browser.

AND even worse - this morning it opened (for the first time) with THREE windows....

1. My usual window
2. this one (the second window currently with only this forum in it)
3. one with JUST "Speed Dial" tab.

I generally switch on about 8AM and off at about midnight.

I've used Opera for years and years. My previous computer died so I got a new motherboard, Windows 11 Pro etc and setup Opera again about 8 months ago. Ever since then I get two windows when I fire up Opera.
I also use Firefox and had the same problem there too. But, with help from an AI, I unset a few options etc and Firefox came good - only one window.
Even with help from the AI I cannot get Opera to stop opening the second window. I've tried setting and unsetting virtually every option but, every time I fire up Opera, up pops the second window. I've asked the AI but nothing works....
Anybody know the secret? I've tried everything so, please, don't suggest the obvious hints.
Thanks in anticipation

I added a filter but popups to the address still popup....

I tried Americas, Europe and Asia - none of them work. From Western Australia.

Is it me or is this a general situation?