Tabs do not restore, although that option is checked. History shows old tabs, not tabs at time of Firefox exit.

I did an update to MacOS 26.6.1. I closed FF. Upon closing, FF seemed to have created another window, but closed the original window. I only had one window open originally, I use tabs not windows. Had to reboot MacOS due to the update. Firefox came up, but the window showing was empty. However, there was a second window, which did have my tabs in it. I never created the empty window.

FF should not be creating new windows upon closing! Think I have seen this before in FF. (Much earlier versions.) Maybe this is a regression?

I will try closing FF again to see if the window and it's tabs are restored. BRB.

Hmm, at least this time, there was no extra windows created. And the tabs were restored for this window. I don't know if this is solved or not. Temporarily it seems ok. I do not know why extra windows are getting created, I'm not deliberately creating them. Is it possible for websites to do this? Can this be prevented by a setting?

For session restore history/backups, see e.g. this rather unrelated thread that however shows some file locations and descriptions how to put an old session store file into the current state.

Is Firefox you default browser? Could something during the update process try to open a web page that would end up as the new window that ends up obscuring your primary window, and would also get restored later? Or that happens even during normal manual restarts, with no extra window, that you're unable to restore your last session?

@jbr I will read that thread, thank you for the link. I will take a look at it.

FF is not my default browser on my Mac. So it may be unlikely that OS updates make that change. Have no idea really why this extra window gets created, but it does, via some process. This has happened before to me, on Linux, years ago, so I'm leaning towards a website, but at the moment I have no proof.

I know of one website that has weird coding, that opens a new window rather than a tab when you view a picture. Wish I could prevent that... Been burned by that in the past. Whenever I visited there, I had to make a conscious effort to close that weird window. But lately, (past year) I have not opened any photos there.

Scripted windows that require certain dimensions can still do it (as per API specs), you can however override these as well with internal prefs: support.mozilla.org/en-US/questions/1592767#answer-1832008 (YMMV, it's not a supported code path)

@jbr This is what I have in my about:config

browser.link.open_newwindow 3 browser.link.open_newwindow.disabled_in_fullscreen true browser.link.open_newwindow.override.external -1 browser.link.open_newwindow.restriction 2

So just change the bottom line from 2 to 0? Are the other settings reasonable?

Thanks for your help so far!

Yes, that is correct.

You can try it here https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_win_open3 (there's a "Try it" button in one of the panels) to see before — after. (=floating window vs. a normal full tab)

Don't forget these will start putting all similar popups into tabs, things like PayPal logins, site surveys etc., so don't be surprised later;]

The other values are defaults and you don't need to look into them too much unless you think they might be related to the functionality that opens new windows from somewhere (each will have some scenario it controls if you search for each of these prefs and read any posts that mention these).

Thanks. I tried that and it works as expected. Hopefully this will help solve the original problem. I saved the default config, so I can revert if necessary. Not ready to say solved, but getting close!

I have to report that the behavior is not as I had hoped. If I click on the red x to end FF, it kills the current window, but doesn't kill FF. If I then kill FF via Firefox>Quit Firefox, clicking on FF gives me a blank screen again. However, I can restore that window. Takes a bit of navigation, definitely not a smooth interface. Basically feels like a lot of work. And doing this restore means I now have 2 windows, not 1. That's not a restore, that's an add window function. I wouldn't think a restore is an add.

If I then terminate via Firefox>Quit Firefox, the pop up then says it will close two windows. So I cancelled the quit. Then I killed the empty window. Now it is safe to do the quit, but not via the red x in the window bar. Can't say that I like this behavior one bit. It doesn't seem natural. Software (and apps) are supposed to make things easier, not increasingly more arcane. However, I'm not sure if this behavior is due to MacOS.

It is good that I could recover the window, but having to do a recovery & a window deletion because I hastily closed FF, well it just seems like unclever behavior. It would seem to me that Firefox could handle this better on a Mac. It doesn't feel cross platform, which I think is one of FF's good points.

So is it a bug? Don't know. But is odd behavior, ie a restore being an add. And the behavior causes the user to have to take additional action, because of the restore.

Pity it is not cross platform. Other OS programs are, like FreeCAD. I've written some cross platform stuff, it can be tricky.

My comment on Mac is some of what they do is just plain dumb... Other things are brilliant. For that matter, to some extent, that can be said for all of the big three OS's. I'm on a Mac right now because their HW is pretty rugged, unlike my previous experience with my last couple of Linux boxes and laptops. And I can use homebrew to pull in some linux like commands.

No, haven't used Windows recently, last time was seven years ago. I was using Linux for decades. And Windows at work. But three years ago, I switched to a Mac at home. When I costed it out - at the time - a like for like system didn't cost much more for a Mac with a decent amount of memory. Nowadays, with the memory shortages, the tradeoff might be different.

Still think the FF behavior is awkward, primarily the restore adding another window, but at least I don't have to start all over again.

Thanks for humoring me. This can be considered solved. Thanks!

If you quit with exactly one window (not closing it beforehand, not /re–/opening anything else), you'll restart also with exactly one window.

If your restore is empty/none, you'll get a default start window/tab. You're not restoring at that point going forwards. You're reopening the last closed window on top of anything else you're doing in the browser at the time — that won't replace or close any other window currently shown. Again, you can't tell what folks have in that startup window and if they did something in there.

As for "last closed window" changes specifically on Mac (i.e. not cross–platform, but conversely tailor made to actually remember one window state back), there's some tickets filed: https://bugzilla.mozilla.org/show_bug.cgi?id=1994097 https://bugzilla.mozilla.org/show_bug.cgi?id=2057911 https://bugzilla.mozilla.org/show_bug.cgi?id=736974

What is concerning here is the original question. That sounded like there was a change in behavior for you — which I'm still failing to see where it could really come from. The steps you describe basically match any older version as well, so I'm trying to find where's the "catch" that made this work to your expectations few weeks ago, but now feels broken.

It felt like something was different. Kept on getting a standard FF window coming up, rather than my window with several (8) open tabs. I'll have to pay more attention to what is happening, although it's tough, since you aren't expecting things to go awry - and then they do.

Have to monitor this some more. Hopefully, the about:config edit that you posted, and my vigilance will keep this multi-window/tab event at bay. Thanks for helping, it is truly appreciated.