This would mean from the last time saved to the recovery they were not saved and there is nothing to restore. Only other way is to look at the history to see if they are still there but if nothing shows up for Restore previous session or history list then there nothing to recovery back.

firefox 58 does not have a "restore previous session" function that i see.

previous versions of firefox had it under the 3 bar menu.

nice job mozilla! removing a very handy function is NOT PROGRESS

You can find it in the History menu and in the "Library -> History" sub menu.

• History -> Restore Previous Session

There is also check "History -> Recently Closed Tabs/Windows"

from the HISTORY tab at top = NO

from MENU> library> history> = NO

If your PC crashes then all of the memory that Firefox was using didn't have time to be saved to disk and your tabs are gone forever had it happen and there is no recovery at this point and I feel you.

firefox is so screwed up. all these problems occurred after firefox 58 update

my firefox is set to "Show windows and tabs from last time"

i am having to force firefox to do this each startup

@jakstock, no this isn't just FF all Browsers do this - I had this happen on previous FF should a crash happen or restore and nothing was saved or backup. If the user fails to backup their sessions or tabs or history or bookmark and problems happen this befalls on the User not FF or Mozilla.

i found that previous sessions, in which there was no FF crash, can be configured to load within FF profile.

it is a pain in the a$$ process of finding the last good saved session and renaming it as the most current saved session.

the process is described here and does work. i would have thought FF developers would have included this manual process as a optional function button. [[Not able to restore previous session after automatic upgrade to Firefox 58.0.1|https://support.mozilla.org/en-US/questions/1205574?utm_campaign=questions-reply&utm_medium=email&utm_source=notification]]

Hi jakstock, if you see this:

• menu button > "Restore Previous Session" is missing
• History menu > "Restore Previous Session" is grayed

Either the file already loaded automatically, or Firefox couldn't find a usable file.

Either way, the next thing to check is:

• "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)

If that doesn't help... If you tend to keep the same tabs open for a long period of time, you might find them in an older session history file.

Could you start by making a backup of your existing session history files? Here's how:

You can open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" Help button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Show in Finder" button. If Finder has highlighted a folder with a semi-random name like a1b2c3d4.default, click into that folder.

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location, or you can copy/paste this folder to your desktop.

What files did you find?

The kinds of files you may find among your sessionstore files are:

• recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session)
• recovery.baklz4: a backup copy of recovery.jsonlz4
• previous.jsonlz4: the windows and tabs in your last Firefox session
• upgrade.jsonlz4-build_id: the windows and tabs in the Firefox session that was live at the time of your last update
• various .js files from Firefox 55 or earlier

Could you take a look at what you have and the date/time of the various files to see whether any of them are likely to have the missing tabs?

To preview the contents of a file, you can drag and drop it onto this page, then click Scrounge URLs: https://www.jeffersonscher.com/res/scrounger.html

That tool is on my site, so please let me know if it doesn't work for you.

jakstock said

it is a pain in the a$$ process of finding the last good saved session and renaming it as the most current saved session. ... i would have thought FF developers would have included this manual process as a optional function button.

A sunny Saturday isn't the best time for either of us to sit down and figure out exactly what happens, but here's my understanding:

When there is a hard crash, it's certainly possible that the recovery.jsonlz4 file, which is frequently updated during your session, could be corrupted and unusable. Firefox creates a backup of that file on a lag, so usually Firefox does reload your last session after a crash.

I suppose it's possible for both of those files to be trashed, and in that case, you may need to use manual methods.

I think in order for Firefox to expand to a situation where you could restore a different old session, someone will need to write that code and contribute it to the project. It is not a high priority for the Firefox developers because for the most part users who need extra session security or session switching features use add-ons for that. Currently (meaning, Firefox 57+), these are the two I hear about:

• https://addons.mozilla.org/firefox/addon/tab-session-manager/
• https://addons.mozilla.org/firefox/addon/my-sessions/

thanks FF 58 update caused my mac to freeze. only escape was hard reboot. that trashed FF from closing properly.

i used the manual method with some limited success.

i will install the session manager addon and hope for the best in the future.

thanks for responding.