This is a very unfortunate problem, but I don't know whether anyone has figured out what causes it. Sometimes the session history file still contains the page addresses if you look at it with a text editor, but perhaps because something in the format of the file is corrupted, the addresses are neither loaded nor displayed, just the blank tabs.

Hopefully some day a user will be able to provide "before and after" files -- a "before" snapshot is saved at every program update, as you can see if you look for old files -- that could be compared to spot any relevant glitches in the data.

Did you create a backup of the available session history files from around that time? If not, perhaps do that now:

(1) To open your profile folder...

If Firefox is still running:

You can 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.

If Firefox is closed:

Type or paste the following into the Windows Run dialog or the system search box and press Enter to launch Windows Explorer:

%APPDATA%\Mozilla\Firefox\Profiles

In that folder, do you see a semi-randomly-named folder? If so, click into it. If you find multiple such folders, find the one that was most recently updated.

(2) Copy out session history files

In your profile folder, scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs.

(3) What files did you find?

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

• recovery.js: 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.bak: a backup copy of recovery.js
• previous.js: the windows and tabs in your last Firefox session
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update (by default, I think there will be up to 10 of these)

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

Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mentioned, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

Let's say hypothetically you have a session history file you want to mine for all the URLs in it. These hopefully would include all the active URLs in the open tabs, but also may contain numerous "back history" URLs and URLs in up to 10 closed tabs per window and up to 3 closed windows. In other words, this data would be "noisy."

To get a "quick-and-dirty" list, you could do this:

(1) Create a copy of the session history file you want to mine for URLs (e.g., recovery.js if it's your live session, previous.js if it's a previous, unrestored session). The fastest way to do this when Firefox is running probably is as follows:

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.

Scroll down and double-click into the sessionstore-backups folder.

Make sure Windows is showing .js and .txt extensions. If you need to turn that on, see http://windows.microsoft.com/en-us/wi.../show-hide-file-name-extensions or http://support.microsoft.com/kb/865219.

Right-click the file you want to back up, click Copy. Then right-click a blank area and choose Paste. Right-click the copy and Rename with a .txt extension.

(2) Open the backup txt file in a Firefox tab. Either drag the renamed file and drop it on an existing page to load the txt file in its place, or right-click the file and choose Open With and use Firefox.

(3) In the tab displaying the session history file, open the Web Console to run a script. You can use either:

• Ctrl+Shift+k
• "3-bar" menu button > Developer > Web Console
• (menu bar) Tools > Web Developer > Web Console

Copy the following script and paste it on the line at the bottom of the console, then press Enter to run it:

var oWindows = JSON.parse(document.body.textContent).windows; for (var w=0; w<oWindows.length; w++){ var oTabs = oWindows[w].tabs; for (var t=0; t<oTabs.length; t++){ console.log(" Window "+(w+1)+" Tab "+(t+1)+": "+oTabs[t].entries[oTabs[t].index-1].url+" "); } }

The console should fill with lines listing the URLs of each open tab from the file. You can select and copy this list and paste it somewhere for safekeeping.

However, if the structure of the file is corrupted, the script may give an error, or you may get useless information. In that case, you'll need a different script. I'll need to hunt around for one that runs in Firefox. If you want to use a Word macro, I have a document for that here: https://www.jeffersonscher.com/res/SessionExtract.docm (you need to use extreme caution in enabling macros in downloaded documents, since this is a way that malware can spread, or in other words, you need to trust me to use that method).

I tried this and I get this error - The character encoding of the plain text document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the file needs to be declared in the transfer protocol or file needs to use a byte order mark as an encoding signature. Thanx in forward for providing me with a different scrips. :)

FicaR94 said

I tried this and I get this error - The character encoding of the plain text document was not declared. The document will render with garbled text in some browser configurations if the document contains characters from outside the US-ASCII range. The character encoding of the file needs to be declared in the transfer protocol or file needs to use a byte order mark as an encoding signature. Thanx in forward for providing me with a different scrips. :)

jscher2000 said

This is a very unfortunate problem, but I don't know whether anyone has figured out what causes it. Sometimes the session history file still contains the page addresses if you look at it with a text editor, but perhaps because something in the format of the file is corrupted, the addresses are neither loaded nor displayed, just the blank tabs. Hopefully some day a user will be able to provide "before and after" files -- a "before" snapshot is saved at every program update, as you can see if you look for old files -- that could be compared to spot any relevant glitches in the data. Did you create a backup of the available session history files from around that time? If not, perhaps do that now: (1) To open your profile folder... If Firefox is still running: You can 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. If Firefox is closed: Type or paste the following into the Windows Run dialog or the system search box and press Enter to launch Windows Explorer: %APPDATA%\Mozilla\Firefox\Profiles In that folder, do you see a semi-randomly-named folder? If so, click into it. If you find multiple such folders, find the one that was most recently updated. (2) Copy out session history files In your profile folder, scroll down and double-click into the sessionstore-backups folder. Save all files here to a safe location, such as your Documents folder. If not too much time has passed, we may be able to use them to recover your lost tabs. (3) What files did you find? The kinds of files you may find among your sessionstore files are:

• recovery.js: 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.bak: a backup copy of recovery.js
• previous.js: the windows and tabs in your last Firefox session
• upgrade.js-build_id: the windows and tabs in the Firefox session that was live at the time of your last update (by default, I think there will be up to 10 of these)

Could you take a look at what you have and the date/time of the various files to see whether you think any of them would have the missing tabs? Note: By default, Windows hides the .js extension. To ensure that you are looking at the files I mentioned, you may want to turn off that feature. This article has the steps: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

I have tried this, too and I think that the files sessionstore.old and sessionstore.js have the time of the previous files, how should I use them for recovery?

FicaR94 said

I tried this and I get this error - The character encoding of the plain text document was not declared.

That's normal when you open a file from your computer. Did you get any other messages after you try to run the script?

FicaR94 said

I think that the files sessionstore.old and sessionstore.js have the time of the previous files, how should I use them for recovery?

The sessionstore.old file likely is much too old; Firefox hasn't created that file since around the time of Firefox 32.

For the sessionstore.js file you found in a different location, 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 new window listing various files and folders in Windows Explorer.

(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.js is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.js
• recovery.bak is deleted from sessionstore-backups

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

(4) Copy in the other sessionstore.js file you want to restore -- Windows should show it right next to sessionstore.old in alphabetical order

Note: the file name must be exact. By default, Windows hides the .js file extension. For best results in renaming file and confirming file names, I recommend showing all file extensions. See: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

(5) Start Firefox and it should read the copied in sessionstore.js 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?

jscher2000 said

FicaR94 said

I think that the files sessionstore.old and sessionstore.js have the time of the previous files, how should I use them for recovery?

The sessionstore.old file likely is much too old; Firefox hasn't created that file since around the time of Firefox 32.

For the sessionstore.js file you found in a different location, 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 new window listing various files and folders in Windows Explorer.

(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.js is moved from the sessionstore-backups folder to the main level of the profile folder and renamed to sessionstore.js
• recovery.bak is deleted from sessionstore-backups

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

(4) Copy in the other sessionstore.js file you want to restore -- Windows should show it right next to sessionstore.old in alphabetical order

Note: the file name must be exact. By default, Windows hides the .js file extension. For best results in renaming file and confirming file names, I recommend showing all file extensions. See: http://windows.microsoft.com/en-us/windows/show-hide-file-name-extensions

(5) Start Firefox and it should read the copied in sessionstore.js 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?

Tried, this now, and all is the same; actually what happened is that I got the same mistake today and now even the new tabs are blank, but luckily I can restore them from history. I didn't get any other messages for script. :)

FicaR94 said

Tried, this now, and all is the same; actually what happened is that I got the same mistake today and now even the new tabs are blank, but luckily I can restore them from history. I didn't get any other messages for script. :)

• If the older file had the same issue as your current file, you may need to use another method of recovering the content.

• If the older file worked briefly but got corrupted again, it might already have been corrupted, or there may be some other problem with your Firefox or an add-on or an external program in properly updating the session history file. Does the problem keep coming back?

FicaR94 said

i am used to working with a lot of tabs open and keeping some important from each time I go online. A while ago, there was a crash on my mozilla, and when I reentered it all my tabs were here, but when I clicked on them they didn't work, just remained blank. ...

Suggestions as follows:

Use the built-in Bookmark All Tabs feature to save important groups of tabs before you close Firefox, "just in case" the session restore feature "chokes". Save the folders of bookmarks for as long as you need them; that feature isn't as transitory as "session restore" is.

Or use a Session Manager type extension that is more robust that what comes with Firefox and will save more than the last solitary session. See what's available for "Sesison Manager"

jscher2000 said

FicaR94 said

Tried, this now, and all is the same; actually what happened is that I got the same mistake today and now even the new tabs are blank, but luckily I can restore them from history. I didn't get any other messages for script. :)

• If the older file had the same issue as your current file, you may need to use another method of recovering the content.

• If the older file worked briefly but got corrupted again, it might already have been corrupted, or there may be some other problem with your Firefox or an add-on or an external program in properly updating the session history file. Does the problem keep coming back?

It hasn't come back since then. Could you tell me about that another method?

FicaR94 said

It hasn't come back since then. Could you tell me about that another method?

Well, good to hear the file is stable. To scrounge URLs from a sessionstore file with a corrupted structure, you need to bypass the structure and just look at the punctuation. There probably are scripts to do this in Firefox, but I do not have any links for them. I created a Word macro that can do that, in a document here: https://www.jeffersonscher.com/res/SessionExtract.docm (you need to use extreme caution in enabling macros in downloaded documents, since this is a way that malware can spread, or in other words, you need to trust me to use that method).