Sorry to hear about this problem. Tab Groups are stored as part of your session (open windows and tabs, and recently closed windows and tabs). Did your whole session go missing, or did the tabs come back "ungrouped"?

Since it has been a week, I'm not sure we'll be able to get your missing tabs back, but please take a look at these menus:

If nothing was restored at all:

Could you check whether either of these are available (not hidden or grayed out):

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

If you got a partial restore:

Check whether you can reopen closed windows:

• "3-bar" menu button > History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows
• (menu bar) History > Recently Closed Windows

As you probably know, any groups you "Save and close" should still be listed on the "List all tabs" drop-down list, with an empty box instead of a colored box. Anything there?

If that doesn't help...

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

(1) To open your profile folder...

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

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

In the first table on the page, find the Profile Folder row and click the "Open Folder" button. This should launch Windows' File Explorer listing the contents of your current profile folder.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

(3) 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 {There might be a snapshot from just before the update?}

Sometimes you can tell from the last modification time which one will have your missing tabs, but not always.

Optional File Contents Preview

These compressed files are a pain to view, so I created a tool on my website to list out their contents. If you want to try that, you can drag and drop it onto the large box on the following page, then click the "Scrounge URLs" button:

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

If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.

The page should list Open Windows, Saved/Closed Tab Groups, and Closed Windows found in the file. If you get a useful list, use the "Save List" button to archive it as a web page of clickable links for future reference.

I'm sorry. i do not see any options of restoring previous session as indicated in the first part of your answer.

As to all the options involving 'history you specify, I do not see how they can help, as most of the sites grouped into the tab groups which disappeared were viewed and grouped/filed in the tab groups iin different times in the last two months. There were about 5 different tab groups each containing 5-10 different sites.

Hello,

About a week ago, after waking up and opening my computer, it seems an update was installed. Since then, all my carefully organized and saved tab groups have disappeared, along with all the sites saved in them.

Please help!

Thank you.

all the tab groups that I have diligently organized and saved - disappeared! The tabs disappeared and all the sites saved within them disappeared also. Please your help

Saved? Did you click Save and close group? That could make it disappear.

I'm sorry. i do not see any options of restoring previous session as indicated in the first part of your answer. As to all the options involving 'history you specify, I do not see how they can help, as most of the sites grouped into the tab groups which disappeared were viewed and grouped/filed in the tab groups iin different times in the last two months. There were about 5 different tab groups each containing 5-10 different sites.

Firefox only remembers the last three closed windows. If you already exhausted the list, then the next step would be to extract the session history files (previous.jsonlz4, upgrade.jsonlz4-nnnn files).

I have this problem as well. The tab groups are one of the features that keep me using Firefox but the feature seems buggy. This is the second time the tab groups have disappeared. If I have to keep re-creating them then there is no point to use this feature.

I am sorry to hear it happened to you also, and twice! since it happened to me I am not putting anything important in those tab groups! A few good people tried to help me in the above dialogue, but it seems there is no real solution, and it is a pity.....

Sorry to hear about this problem. Tab Groups are stored as part of your session (open windows and tabs, and recently closed windows and tabs). Did your whole session go missing, or did the tabs come back "ungrouped"? Since it has been a week, I'm not sure we'll be able to get your missing tabs back, but please take a look at these menus: If nothing was restored at all: Could you check whether either of these are available (not hidden or grayed out):

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

If you got a partial restore: Check whether you can reopen closed windows:

• "3-bar" menu button > History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows
• (menu bar) History > Recently Closed Windows

---

As you probably know, any groups you "Save and close" should still be listed on the "List all tabs" drop-down list, with an empty box instead of a colored box. Anything there?

---

If that doesn't help...

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

(1) To open your profile folder...

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

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

In the first table on the page, find the Profile Folder row and click the "Open Folder" button. This should launch Windows' File Explorer listing the contents of your current profile folder.

(2) Copy out session history files

In your profile folder, double-click into the sessionstore-backups folder. Save all files here to a safe location such as your Documents folder.

(3) 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 {There might be a snapshot from just before the update?}

Sometimes you can tell from the last modification time which one will have your missing tabs, but not always.

Optional File Contents Preview

These compressed files are a pain to view, so I created a tool on my website to list out their contents. If you want to try that, you can drag and drop it onto the large box on the following page, then click the "Scrounge URLs" button:

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

If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.

The page should list Open Windows, Saved/Closed Tab Groups, and Closed Windows found in the file. If you get a useful list, use the "Save List" button to archive it as a web page of clickable links for future reference.

I tried all this but "save list" appears greyed out. So weird to find a bug in Firefox. It's consistent. Every time. All my groups are closed and there is no obvious way to reopen them. Why?

jscher2000 - Support Volunteer said

Optional File Contents Preview These compressed files are a pain to view, so I created a tool on my website to list out their contents. If you want to try that, you can drag and drop it onto the large box on the following page, then click the "Scrounge URLs" button: https://www.jeffersonscher.com/ffu/scrounger.html If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab. The page should list Open Windows, Saved/Closed Tab Groups, and Closed Windows found in the file. If you get a useful list, use the "Save List" button to archive it as a web page of clickable links for future reference.

I tried all this but "save list" appears greyed out.

What if instead of using the "Scrounge URLs" button, you use the "Unstructured URL List" button? That doesn't give as useful a list, but can that one be saved?

It's consistent. Every time. All my groups are closed and there is no obvious way to reopen them. Why?

Is Firefox restoring your session normally otherwise, or is the whole session getting lost? Oh wait, let me reply over here: https://support.mozilla.org/questions/1547816