It also blew away my home page, which uses an add on address. Maddening!

And all my add-ons are gone! What the hell did Mozilla do?

Is there an upgrade.js file present in the sessionstore-backups folder?

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

You will normally find these files in the sessionstore-backups folder:

• previous.jsonlz4 (cleanBackup: copy of sessionstore.jsonlz4 from previous session that was loaded successfully)
• recovery.jsonlz4 (latest version of sessionstore.jsonlz4 written during runtime)
• recovery.baklz4 (previous version of sessionstore.jsonlz4 written during runtime)
• upgrade.jsonlz4-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.jsonlz4 to replace the current file (make a backup copy of the current sessionstore.jsonlz4).

Firefox 56+ releases compress the files in the sessionstore-backups folder with LZ4 (.jsonlz4 instead of .js), so it is no longer easy to inspect them.

Thanks for your detailed reply.

Where to I find the sessionstore-backups folder? I followed your instructions but do not see it.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder

Copy/Pate this into the about:profiles address bar where the internet/URL is next to the padlock

Follow the rest of cor-el's answer.

Note : Firefox 56.0.2 is current release https://www.mozilla.org/firefox/all/ Full Version Installer Note : Firefox 57 Quantum release date Nov 14th https://www.mozilla.org/en-US/firefox/quantum/ Note : Legacy Extensions will be disabled and or removed.

Please let us know if this solved your issue or if need further assistance.

OK, I found it. 4 questions:

1. What do each of these files represent?

2. Which of them should I be copying to the folder with the main profiles?

3. Where is the main profile located (in which folder, with path please)?

4. I imagine I will have to delete the current sessionstore.jsonlz4 file in the folder in which the main profile is located before I can rename the file I'm pasting in there?

Do you have an upgrade.js (or jsonlz4) file with a date stamp of around the time the update occurred?

The point is to copy a file that is located in sessionstore-backups folder to the main profile folder and rename this sessionstore.jsonlz4 or sessionstore.js preserving the original Firefox. Firefox 56+ releases compress the files in the sessionstore-backups folder with LZ4 (file extension is.jsonlz4 instead of .js).

Please back up all those files to a safe location in case they get lost in the shuffle.

In the best case scenario, and "update" snapshot was created that will have the missing tabs.

If your home page was reset and you lost your add-ons, possible a Refresh ran. Do you see a new Old Firefox Data folder on your desktop with freshly updated files inside?

@cor-el: Yes, I do have upgrade.jsonlz4 file with a date stamp of around the time the update occurred

@jscher2000: Yes, I have copied those to a separate location. And yes, my home page was reset and I lost my add-ons. I do you see an Old Firefox Data folder on my desktop with 1 freshly updated file inside. What do I do with it?

And I still need to know to where I'm supposed to put the upgrade.jsonlz4 file.

Thanks

craigj1 said

I do you see an Old Firefox Data folder on my desktop with 1 freshly updated file inside. What do I do with it?

It depends on what you want to recover. You can make selective use of settings files from the folder, or you can try a wholesale restoration of everything as of the moment of the Refresh. There's no one-click method for either of those.

• Recovering important data from an old profile
• I did a Reset of Firefox - How do i get add my 'Old firefox data' back?

@cor-el: Yes, I do have upgrade.jsonlz4 file with a date stamp of around the time the update occurred
...
And I still need to know to where I'm supposed to put the upgrade.jsonlz4 file.

Note: Not yet tested in Firefox 56

To try swapping in an older session history file so Firefox will load it, the standard "manual swap" method is as follows (assuming Firefox is still running):

(1) From inside Firefox, open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > 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, click the "Show Folder" button. This should launch a Windows Explorer window listing the various files and folders in your profile.

(2) Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > "power" button
• (menu bar) File > Exit

Pause while Firefox finishes its cleanup -- these changes should occur:

• recovery.jsonlz4 is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.jsonlz4
• recovery.baklz4 is deleted from sessionstore-backups

(3) Once Firefox has stopped updating things, while viewing the main level of the profile folder, rename sessionstore.jsonlz4 to OLDsessionstore.jsonlz4

If you see an older sessionstore.js or sessionstore.bak file, move it somewhere else or delete it.

(4) Copy in the other file you want to restore, and rename it with the name appropriate for its format:

• Uncompressed .js file => sessionstore.js
• Compressed file => sessionstore.jsonlz4

(5) Start Firefox and it should read the swapped in sessionstore file and restore whatever was in the substitute file; if you do not have Firefox set to restore your previous windows and tabs automatically, use History > Restore Previous Session

Any luck?

Just getting around to this today (I didn't get an e-mail notification of this reply). Will attempt tonight.

Thank you for taking the time to provide such a thorough answer.

Too much time has passed and I never got around to trying this. I will, but now I Mozilla's latest update has caused yet more mayhem that needs to be dealt with immediately. Apparently, the speed dial add-in that has been a godsend for me "no longer meets Firfox's standards and was deactivated".

Why don't these people warn us users when a favorite add-on or plug-in is about to be deactivated? No, we just have to wake up one day and find it's gone - without having been given any opportunity to migrate over to another one. Brilliant!

And I suppose Mozilla has ended their relationship with Pocket, since the icon for that app has vanished, as it is from the pulldown menu.

Everyone keeps telling me I should move to Chrome. With these latest aggravating shenanigans, I just may have to. I see no reason to stay with a browser whose developers keep creating headaches with each successive update, no doubt in the name of progress. Leave well-enough alone, or if you must make changes, LET US KNOW BEFORE YOU DO.

Ah, I now see - I think - why the file is not found: All my plug-ins and add-ons have been removed!'

Yes, I understand the challenges with Firefox 57 and unwelcome surprises.

craigj1 said

Apparently, the speed dial add-in that has been a godsend for me "no longer meets Firfox's standards and was deactivated".

Firefox 57 no longer runs Legacy extensions. However, many extensions have been updating in the background to Firefox 57 compatible versions. Could you look up which extension you were using? Please open the Add-ons page using either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions. Above the list there, do you see a link to "Show Legacy Extensions"? If so, please click that.

Why don't these people warn us users when a favorite add-on or plug-in is about to be deactivated? No, we just have to wake up one day and find it's gone - without having been given any opportunity to migrate over to another one. Brilliant!

If you had any reason to visit the Add-ons page in Firefox 55-56, you would have noticed a warning there, but if you didn't need to venture in there, then I'm not sure where you would have seen it.

And I suppose Mozilla has ended their relationship with Pocket, since the icon for that app has vanished, as it is from the pulldown menu.

In the address bar you'll see a page actions menu icon that looks like ••• -- if you click that, you should find a "Save Page to Pocket" entry, and you can move it just to the right of that icon by right-clicking it and choosing Move to Address Bar.

If the item is missing, Pocket might be disabled, although if it worked for you in Firefox 56, I don't know why that would be. If you need to check:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful or accepting the risk.

(2) In the search box above the list, type or paste pock and pause while the list is filtered

(3) If the extensions.pocket.enabled preference is bolded and "modified" or "user set" to false, double-click it to restore the default value of true

Thank you for your comprehensive reply, jscher2000.

I did something - not sure what - so that the "Add to pocket" icon ia back - next to the address by, now (I actually have two icons - an "add to pocket" one and a "save to pocket one".

I also have an icon for "In My Pocket", the suggested "upgrade" I installed.

But now my downloads icon is missing....  :(

I think the built in one has the mouseover text "Save to Pocket" (at least on U.S. English). I don't know where Add to Pocket is coming from; possibly a second add-on?

(The official add-on doesn't appear on the Extensions list on the Add-ons page, but it's on the Features list of the Troubleshooting Information page.)

For the Downloads icon, could you check the available icons in the Customize panel: Customize Firefox controls, buttons and toolbars.

Yes, I checked that for the Downloads icon. Not there.

Remarkable.

Oh wait... the problem is that you haven't made any downloads during the current session. As a streamlining feature, the arrow is set to hidden until there is a download to show on it. After it appears if you use right-click > Remove from History on all the listed downloads, the button hides again.

If you want to prevent the icon from hiding, you probably need to use a custom style rule such as:

/* Never Hide Downloads Button */
#downloads-button[hidden="true"]{
  display: -moz-box !important;
}

You can apply custom style rules to Firefox's interface by creating a userChrome.css file. If you've never worked with one before, you can find more info on my website here: https://www.userchrome.org/