Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox deleted the content of background tabs after crashing upon upgrade

more options

I usually operate Firefox with many tabs open and I use the "open tabs/windows from last time" on startup... ...it happens that I may work on the same session for more than a month.

On March 19th I had a session in Firefox v59 with some newly opened tabs, while the others were "background loaded", from the previous time I had restarted the application.

I set Firefox to download and install the latest v59.0.1 of Firefox, but I had not restarted yet, to complete installation.

At some point (after midnight, early March 20th), because I had other heavy applications running, Firefox crashed.

I started FF again, and it loaded the previous session, as chosen in the settings.....HOWEVER I noticed that ALL background tabs of the previous session (when it crashed) had been REPLACED with a "new tab".

...that is, the number of tabs of the previous session was opened, but the content of most tabs had been deleted and replaced with a "new tab", while the few that had been active in the previous session were preserved.

For some reason this crash also deleted all User Sessions I had saved with the extension "Session Boss", so I was unable to recover them.

This has been a very damaging event, as I was due to write some articles and I had organized the material in the active session, and saved it in Session Boss sessions, for safety... ...all of this was deleted... :(

I also had "Firefox Sync" enabled, which proved to be a problem, because it replaced the active session in the cloud with the "broken" session; So when I tried to recover the open tabs in my other pcs, only the few tabs that were preserved were synced (whereas, if I had disabled it right away, the "healthy" session would have synced to my other devices).

Not knowing what to do and fearing that keeping the Browser open would create further problems, I did the following 1) I copied some files that seemed related to the "session" from the profile folder to another folder....and then I closed the browser I copied the - "sessionstore-backups" folder (which contains some files just before the crash) - "minidumps" folder - "browser-extension-data" folder

2) After closing the browser, I copied all the profile folder of FF to another location.


I have opened a few files in the "sessionstore-backus" folder, e.g. "previous.jsonlz4" and "upgrade.json***" and they do seem promising, e.g. I can make out it contains many titles and urls of my session, but it is also in characters I cannot use.

Is there a way for me to use these files to restore my full session?

P.S.

1) I am writing this message from another PC/browser. Not sure if I should open FF that crashed; afraid it could mess something up

2) Session Manager extension is irreplaceable! Something has to be done to bring it back!

I usually operate Firefox with many tabs open and I use the "open tabs/windows from last time" on startup... ...it happens that I may work on the same session for more than a month. On March 19th I had a session in Firefox v59 with some newly opened tabs, while the others were "background loaded", from the previous time I had restarted the application. I set Firefox to download and install the latest v59.0.1 of Firefox, but I had not restarted yet, to complete installation. At some point (after midnight, early March 20th), because I had other heavy applications running, Firefox crashed. I started FF again, and it loaded the previous session, as chosen in the settings.....HOWEVER I noticed that ALL background tabs of the previous session (when it crashed) had been REPLACED with a "new tab". ...that is, the number of tabs of the previous session was opened, but the content of most tabs had been deleted and replaced with a "new tab", while the few that had been active in the previous session were preserved. For some reason this crash also deleted all User Sessions I had saved with the extension "Session Boss", so I was unable to recover them. This has been a very damaging event, as I was due to write some articles and I had organized the material in the active session, and saved it in Session Boss sessions, for safety... ...all of this was deleted... :( I also had "Firefox Sync" enabled, which proved to be a problem, because it replaced the active session in the cloud with the "broken" session; So when I tried to recover the open tabs in my other pcs, only the few tabs that were preserved were synced (whereas, if I had disabled it right away, the "healthy" session would have synced to my other devices). Not knowing what to do and fearing that keeping the Browser open would create further problems, I did the following 1) I copied some files that seemed related to the "session" from the profile folder to another folder....and then I closed the browser I copied the - "sessionstore-backups" folder (which contains some files just before the crash) - "minidumps" folder - "browser-extension-data" folder 2) After closing the browser, I copied all the profile folder of FF to another location. I have opened a few files in the "sessionstore-backus" folder, e.g. "previous.jsonlz4" and "upgrade.json***" and they do seem promising, e.g. I can make out it contains many titles and urls of my session, but it is also in characters I cannot use. Is there a way for me to use these files to restore my full session? P.S. 1) I am writing this message from another PC/browser. Not sure if I should open FF that crashed; afraid it could mess something up 2) Session Manager extension is irreplaceable! Something has to be done to bring it back!
Attached screenshots

Modified by Bourdieu

All Replies (12)

more options
more options
more options

Pkshadow said

https://addons.mozilla.org/en-US/firefox/addon/tab-session-manager/

I had a Session extension installed, Session Boss ....however, the crash and/or the update not only broke my session, but also DELETED ALL SESSIONS saved with the extension.

more options

Pkshadow said

Sorry, not my thing : PROFILES fyi for the future :

Thank you for your response Thankfully I did not lose my bookmarks etc. beside the last active session, profile is fully functional....except the aforementioned problem that arose.

I did make some progress though. Jefferson from the support team here offered a handy tool, that allowed to me recover URLs from past automatically saved sessions, in the "sessionstore" folder.

https://www.jeffersonscher.com/res/scrounger_json.html

I am not there yet, but this helped a lot.

The root / cause of the issue though should be investigated, but I have no clue with regards to technical matters.

The issue at hand is 1) How come the background tabs lost their url content (and retained only the title) 2) How come the crash And / Or the upgrade to the latest version (from the immediate before it) also deleted all extension data from "Session Boss" extension.

Modified by Bourdieu

more options

With any program that updates it is advisable and I use strongly to shut down everything to the bare bones and save your work before updating and update now not later.

When you put off updating you also increased stress on Firefox which was holding all that data to update as well as your ram and something gave as session information takes large quantities of ram.

There is no need to investigate. It is user interaction or the lack of it that caused the issue.

In future, save your sessions and shut down things you do not need and update.

more options

This will give you a idea of amount of data plus time frame sessions use and how often. https://www.servethehome.com/firefox-is-eating-your-ssd-here-is-how-to-fix-it/

more options

Bourdieu said

The issue at hand is
  1. How come the background tabs lost their url content (and retained only the title)
  2. How come the crash And / Or the upgrade to the latest version (from the immediate before it) also deleted all extension data from "Session Boss" extension.

For #1, "new tab" replacing actual tabs happens from time to time, and I've never seen an explanation for it, or reliable steps to reproduce the issue. Earlier this year, I had something like that happen to me for the first time ever. I backed up my session files immediately and then restarted Firefox, but on restart, everything was fine, so I don't know what was going on.

For #2, Session Boss and Tab Session Manager use a single file named storage.js and it's certainly possible the file became corrupted due to bad timing of the crash (if the extension was updating the file or perhaps something else). I think this may be an issue that needs to be escalated because extensions may store many kinds of data that no one wants to lose in a crash.

Firefox allows extensions to use database storage as well as the storage.json file, so extension authors could use that for backups from time to time. I don't know how much complexity that would add. (Database access is blocked in private windows, but presumably you don't want your session saved if you are using a private window, so at least that limitation is not an issue for these extensions.)

more options

In the other thread, you mentioned a "good session" from mid-February, which was over a month ago. One source of potentially newer files would be "shadow copies" made by Windows when you last did Windows updates. To check for any of those:

Open your current Firefox settings (AKA Firefox profile) folder using either

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

In the first table on the page, in the Profile Folder row, click the "Open Folder" button.

In your profile folder, double-click into the sessionstore-backups folder.

Right-click recovery.jsonlz4 and click Properties. Then click the Previous Versions tab. This will take some time to populate because Windows will search old restore points to see which ones have this file. If you see one from a more recent date, you can use the "Copy" button to extract it to a safe location (i.e., not overwriting your current file).

I suggest you repeat with recovery.baklz4 and previous.jsonlz4 in case either of those has a more recent shadow copy.

If it's possible Firefox was closed the last time Windows made shadow copies, you could exit out of Firefox and let it create the sessionstore.jsonlz4 file at the main level of the profile folder (one level up from sessionstore-backups) and repeat the exercise there. But if you keep Firefox open nearly all the time, there might not be any shadow copies.


Note to other readers: Windows 7 was the last version with this kind of Previous Versions tab. For Windows 8, 8.1 and 10 you can use a utility program to browse restore points:

First, make sure Windows is set to show hidden files and folders: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

Next, try one of these programs:

Within each restore point you check, you can explore along this path to a file you might be able to use:

\Users\your-user-name\AppData\Roaming\Mozilla\Firefox\Profiles\

more options

jscher2000 said

Bourdieu said
The issue at hand is
  1. How come the background tabs lost their url content (and retained only the title)
  2. How come the crash And / Or the upgrade to the latest version (from the immediate before it) also deleted all extension data from "Session Boss" extension.

For #1, "new tab" replacing actual tabs happens from time to time, and I've never seen an explanation for it, or reliable steps to reproduce the issue. Earlier this year, I had something like that happen to me for the first time ever. I backed up my session files immediately and then restarted Firefox, but on restart, everything was fine, so I don't know what was going on.

For #2, Session Boss and Tab Session Manager use a single file named storage.js and it's certainly possible the file became corrupted due to bad timing of the crash (if the extension was updating the file or perhaps something else). I think this may be an issue that needs to be escalated because extensions may store many kinds of data that no one wants to lose in a crash.

Firefox allows extensions to use database storage as well as the storage.json file, so extension authors could use that for backups from time to time. I don't know how much complexity that would add. (Database access is blocked in private windows, but presumably you don't want your session saved if you are using a private window, so at least that limitation is not an issue for these extensions.)

If I can speculate on the issue of which tabs get corrupted, I would say that in my case it as the tabs which were background loaded, i.e. they were not active in that current session and were in lazy/background loaded via the "show windows and tabs from last time".

I will communicate this suggestion to the developer of "Session Boss". Hopefully it will be sorted out.

Sad part is, that crash actually happened because "Session Boss" gave the confidence that I would not lose any session (if I had saved them, even if the current session was corrupted)... ...so I put too much stress on the computer, doing many things while having this huge session with the browser open for many days...

...good for me...

more options

jscher2000 said

In the other thread, you mentioned a "good session" from mid-February, which was over a month ago. One source of potentially newer files would be "shadow copies" made by Windows when you last did Windows updates. To check for any of those: Open your current Firefox settings (AKA Firefox profile) folder using either
  • "3-bar" menu button > "?" Help > Troubleshooting Information
  • (menu bar) Help > Troubleshooting Information
  • type or paste about:support in the address bar and press Enter
In the first table on the page, in the Profile Folder row, click the "Open Folder" button. In your profile folder, double-click into the sessionstore-backups folder. Right-click recovery.jsonlz4 and click Properties. Then click the Previous Versions tab. This will take some time to populate because Windows will search old restore points to see which ones have this file. If you see one from a more recent date, you can use the "Copy" button to extract it to a safe location (i.e., not overwriting your current file). I suggest you repeat with recovery.baklz4 and previous.jsonlz4 in case either of those has a more recent shadow copy. If it's possible Firefox was closed the last time Windows made shadow copies, you could exit out of Firefox and let it create the sessionstore.jsonlz4 file at the main level of the profile folder (one level up from sessionstore-backups) and repeat the exercise there. But if you keep Firefox open nearly all the time, there might not be any shadow copies.

Note to other readers: Windows 7 was the last version with this kind of Previous Versions tab. For Windows 8, 8.1 and 10 you can use a utility program to browse restore points:

First, make sure Windows is set to show hidden files and folders: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files

Next, try one of these programs:

Within each restore point you check, you can explore along this path to a file you might be able to use:

\Users\your-user-name\AppData\Roaming\Mozilla\Firefox\Profiles\

Unfortunately I have disabled the creation of "Restore Points" in the OS... ...up till this moment I never saw any reason for it; in the past in whatever issue I had with the OS or other software, System Restore never helped me, so I ended up opting for having more space free in a 120GB ssd.

I have to thank you again for 1) Helping me to start understanding how FF works in this regard 2) Providing the tools that helped me get rid of desperation, really.

I just wish there was an extension as reliable as "Session Manager" in Firefox Quantum...current ones - either use bookmarks to store sessions (not acceptable for someone reading / organizing / bookmarking / tagging tens and tens of articles a day) - or seem vulnerable to crashes, being in the infancy to a large extent.

(also If Firefox ever changes their bookmarks Tagging system I am screwed)

In Chrome, Session Buddy is quite nice (allowing the export of sessions in a variety of formats).

Not trusting the currently available session extensions and being a heavy FF user, I am unfortunaely contemplating switching to Cyberfox / Waterfox, in order to use "Session Manager" in which I have tens of saved session, actually.

more options

Tab Session Manager has an Export option as a backup to storage.js, but it appears Session Boss doesn't have one yet. (Comparison screenshots attached.) I can't tell whether it is planned.

more options

Bourdieu said

If Firefox ever changes their bookmarks Tagging system I am screwed

Keep those bookmark backups in a safe place!