There are 2 things you can do, backup :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Let's see oh ya it is a computer program.

Since you know all the words and the locations of the files please check your backups :

• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

As your asking questions that Volunteer Support can't and will not answer, please go to the 3 Bar Menu --> Help --> Submit Feedback of your Constructive and informative information/suggests that will be looked at by a team and considered for future versions. Include all things regarding that volunteers can not answer, such as things in Capital letters, euphemisms and generally any thing that has nothing to do with the issue that you have come to seek help for

First off, what have you done as far as looking into your problems with Firefox crashing? https://support.mozilla.org/en-US/kb/firefox-crashes-troubleshoot-prevent-and-get-help

Second, Firefox hasn't had session crash recovery for "a decade".

Session Manager extensions aren't made by Mozilla, they are created by 3rd party developers. As to why that type of extension hasn't been available for Quantum, that is a question for the developers of those Legacy extensions; and while you are asking them, ask about their progress towards a WebExtension version of their defunct product. Over the last 3 or 4 months a number of new API's become available that might help with "session" extensibility.

As far as your reference to User Reviews for Tab Session Manager - best to take that up with the developer of that extension. His Support "issues" page is here: https://github.com/sienori/Tab-Session-Manager/issues It has been a struggle for extension developers to adapt to WebExtensions vs the old Legacy extensions; they had to start from scratch or adapt the WE code used in Chrome which is similar but a little different in some ways. It;s a learning curve to overcome for many developers. Plus new API's are coming out of Mozilla fairly often, to solve some of the issues mentioned here: https://www.reddit.com/r/firefox/comments/7m8nvx/can_session_manager_tab_session_manager_coexist/drslt43/

Pkshadow said

There are 2 things you can do, backup :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Let's see oh ya it is a computer program. Since you know all the words and the locations of the files please check your backups :

• sessionstore.jsonlz4 for open tabs and pinned tabs (see also the sessionstore-backups folder)

As your asking questions that Volunteer Support can't and will not answer, please go to the 3 Bar Menu --> Help --> Submit Feedback of your Constructive and informative information/suggests that will be looked at by a team and considered for future versions. Include all things regarding that volunteers can not answer, such as things in Capital letters, euphemisms and generally any thing that has nothing to do with the issue that you have come to seek help for

Where have I used euphemisms? I believe "lz4" itself is an euphemism and bulk.

the-edmeister said

First off, what have you done as far as looking into your problems with Firefox crashing? https://support.mozilla.org/en-US/kb/firefox-crashes-troubleshoot-prevent-and-get-help Second, Firefox hasn't had session crash recovery for "a decade". Session Manager extensions aren't made by Mozilla, they are created by 3rd party developers. As to why that type of extension hasn't been available for Quantum, that is a question for the developers of those Legacy extensions; and while you are asking them, ask about their progress towards a WebExtension version of their defunct product. Over the last 3 or 4 months a number of new API's become available that might help with "session" extensibility. As far as your reference to User Reviews for Tab Session Manager - best to take that up with the developer of that extension. His Support "issues" page is here: https://github.com/sienori/Tab-Session-Manager/issues It has been a struggle for extension developers to adapt to WebExtensions vs the old Legacy extensions; they had to start from scratch or adapt the WE code used in Chrome which is similar but a little different in some ways. It;s a learning curve to overcome for many developers. Plus new API's are coming out of Mozilla fairly often, to solve some of the issues mentioned here: https://www.reddit.com/r/firefox/comments/7m8nvx/can_session_manager_tab_session_manager_coexist/drslt43/

But Firefox has a native crash session recovery, which failed a few times and "restore previous session" is grayed out.

Why is it grayed out? Firefox's crash recovery has failed like that many times during the last 10 years. Firefox is good at losing your session.

Why does Firefox deny access to the session? How can I hack it not to be grayed out?

What are the first 3 Google results when typing "jsonlz4"? https://imgur.com/9FpH1QV JsonLz4 is obviously more headache than good. (Sorry for the critics)

Hi, we are not talking about google or the results, your issue is yours. The problem is with your files and no one else s plus the fact that there is something corrupted which is causing the greyed out.

So, it boils down if you had been creating backups as should be done daily when it is important information that is irreplaceable you could have been fixed in a couple of minutes. As per my 1st post.

So if you had done the conventional by backing up and not blaming Firefox for the lack of your support then : euphemisms : a mild or indirect word or expression substituted for one considered to be too harsh or blunt when referring to something unpleasant or embarrassing.

Oh wait, I tested session restore and this time, somehow, it worked successfully.

Last time it failed, but this time it actually worked. Mysterious.

Pkshadow said

Hi, we are not talking about google or the results, your issue is yours. The problem is with your files and no one else s plus the fact that there is something corrupted which is causing the greyed out. So, it boils down if you had been creating backups as should be done daily when it is important information that is irreplaceable you could have been fixed in a couple of minutes. As per my 1st post. So if you had done the conventional by backing up and not blaming Firefox for the lack of your support then : euphemisms : a mild or indirect word or expression substituted for one considered to be too harsh or blunt when referring to something unpleasant or embarrassing.

I know what an euphemism is, but still thanks.

Actually, I always have backed up my session daily using "Tab URL copier", but I was just wondering why Firefox's built-in session restore does work occasionlly only (it just worked).

Hi, ya, mystery. Something may have updated in the way of Security/Firefox or your OS or something was just tortured enough for the time being.

Sometimes it just is.

So use Backup with URL's supplied as can always replace the program.

Backup in other ways like copy whole folder outas well as add-ons :

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data
• https://addons.mozilla.org/firefox/search/?platform=windows&q=session%20backup
• https://addons.mozilla.org/firefox/search/?platform=windows&q=sync

If these are hidden or grayed out --

• "3-bar" menu button > Restore Previous Session
• (menu bar) History > Restore Previous Session

-- then either Firefox already restore the session history file, or Firefox was not able to restore it.

Either way, the thing to do to in that situation is to check either:

• "Library" toolbar button > History > Recently Closed Windows (and within each restored window, Recently Closed Tabs)
• (menu bar) History > Recently Closed Windows (and within each restored window, Recently Closed Tabs)

In the case that the session was restored but some windows read as closed, you would be able to re-open some of them.

In the case that restoration failed, perhaps there would be a relevant message in the Browser Console (Ctrl+Shift+j) but often there are so many messages that early ones are gone by the time you open it.

Do you have Firefox set to automatically restore at startup (i.e., after a normal shutdown)? That's helpful to avoid inadvertent session loss.

File compression reduces disk write time. These files can get very large and with a default update interval of 15 seconds, apparently that became an issue.

If you want to extract an LZ4-compressed session history file, you can use my page here:

https://www.jeffersonscher.com/ffu/scrounger.html

Note that Firefox works best if you use the "Restore Previous Session" startup choice. With this choice Firefox will regularly write a sessionstore backup to the hard drive that is more reliable than the other startup choices.