What happened to Firefox's "Restore session" feature?

[RLynwood]

Here I go again. After another long discussion, I'm finding that Firefox's "Restore session" feature seems to have returned and be working. Every time I've shut the computer down, leaving all my apps running (which Kub. shuts down in the process of shutting down), Firefox comes up blank but with the Restore session option available. And it always works when I click it. So, again, tentatively, I'll consider this problem to have been solved. But I have no idea of why/how.

[RLynwood]

You may be right, especially with snapped Fx, which is what I have. I suspect that that's part of the problem. I may well follow Schwarzer Kater's advice and install in addition an unsnapped Fx. However, good news: tonight I had to reboot my system to check another problem. Taking advantage of one of Kub's fantastic features, I just clicked restart, not worry about closing all my apps 'cause Kub remembers them and pulls them all--almost all--back up during the reboot. This time, Fx came up with the blank page again, but this time it displayed the "restore session" button, just not where I expected it. It was toward the bottom of the blank page in the center. But it was large, virtually unmistakable, about two inches wide and one inch high as I recall. So, with that one click, I was back in business. Come to think of it, however, I haven't seen that nagging alert about Fx's needing to be shut down to downlaod an update. Maybe this reboot took care of that, and the update solved the "restore session" bug.

[bweinel]

Another thing which can potentially cause problems in Firefox is add-ons. I have previously found issues with some add-ons which can cause Firefox to randomly crash. Once the offending add-on has been removed or deactivated... Firefox runs perfectly again. This is particularly a problem with older or 'out-of-date' add-ons installed in newer versions of Firefox.

cheers,
bill

[RLynwood]

Thanks. I didn't know that Fx had a reputation for bugginess. But your experience seems to match mine for the last few weeks. And that's when I've gotten those blank pages--with no session restore option--when I call it up again. Your experience is very helpful. Glad to know about it.

[claydoh]

Fx has crashed so many times (~ 3-4) over the last few weeks

Don't rule out a buggy Firefox. I have seen it go poof! a couple of times on me in the past week or so, and I use the PPA version. But twice for me is not a pattern, just yet.
(I do sometimes live on the edge a little, sometimes, so...who knows)

[RLynwood]

P.s. Yeah, I wish I knew why Fx has crashed so many times (~ 3-4) over the last few weeks, since establishing Kub. on the flash drive.

[RLynwood]

More good advice. Thanks. Not sure now how I'll use it, but I definitely will keep it in mind.

[Schwarzer Kater]

The interval how often sessions are stored in Firefox is set in milliseconds in -> about:config -> browser.sessionstore.interval .
This should be no different for the Snap version.

The default is 15000 = 15 seconds. If you started Firefox and it crashed immediately it could be possible that a session not has been stored again at this point AFAIK - or the file indeed is corrupted.

Enter a lower value if you want to save your session even more often or a much higher value if you want to reduce the writes on your SSD/USB stick (I have set mine to 600000 = 10 minutes - the last time Firefox crashed on one of my computers was about 5-6 years ago, though).

[RLynwood]

Thanks, again. Your suggestion seems to provide what I want. I'll think about it and probably play with it ioto learn about it.
I'm not sure it'll help in troubleshooting my problem, either, but you seem to have had a good idea. Maybe it will solve it.

[claydoh]

Deleting, or rather moving/renaming the folder would cause a new empty profile to be created.
the entire .mozilla folder is what you copy to back up your entire Firefox config, bookmarks, extensions, and whatnot.

If you want the specific full path, you can open about:profiles in FF to see this, and even add a new profile if you wanted to play with that. Not sure if that helps in troubleshooting UI issues, though.

The easiest way to test if the profile is borked is to close FF, rename the .mozilla dir that contains your profile, and restart the browser.
If it doesn't work, it is easy-peasy to close FF, delete the newly created directory, and un-rename the original one.

[RLynwood]

Now we're getting somewhere; this looks useful and like it might be on the right track. But it looks scary. A folder labeled "snap" contains a folder each for Firefox and Chromium. Firefox's folder contains four folders labeled 2579, 2605, Common, & Current, and the word 'current' is italicized. Common contains ~/.mozilla/firefox. That contains four folders/directories & a profiles.ini file. The directory <zemdnky6.default> contains 16 directories and lots of files. If I were to delete this Firefox directory, what would replace it? What would prevent that from borking Firefox?

[claydoh]

after Fx has crashed

If this happened, you may have a corrupt config. Maybe try (re)moving your ~/.mozilla/firefox dir, and see if a fresh profile fixes the UI.

[RLynwood]

"Do remember that there won't be a 'restore previous session' option unless you have one to restore."
I'm well aware of that. I don't try to restore a previous session unless Fx has crashed, then comes back up without the previous session's tabs. I always select the restore previous session's tabs in the Settings General page: "open previous windows and tabs" when setting up Firefox in the beginning of using it.
And, yes, I've seen the entry you showed (thanks for that clarity) and used it many times. As I said in my initial post in the conversation, that's how I knew it should be there, but it isn't there, has't been there after Fx has crashed while using Kub. in this flash drive.
If I can't solve this problem, maybe I will have to resort to one of those extensions you mentioned.

[claydoh]

Do remember that there won't be a 'restore previous session' option unless you have one to restore. Basically, anything past opening the application. After opening any tabs or pages, the old session is lost.
There are numerous extensions that can save and restore them, though.

A freshly opened browser vs one that have been used:

[RLynwood]

I understand that and looked there first (the hamburger), of course. It is not there; it just isn't there, not top, bottom not in the history list, not even in the "manage history" link. That's why I'm asking here. I hadn't thought of the Menu bar's history, but I'm pretty sure it wasn't there, either.