hello celine.ganty,

To restore this data:

On the desktop you should see a folder called 'Old Firefox Data' open it and copy all the data by highlighting and selecting everything in that folder, then right click and select copy. Now open FIrefox. Head on over to about:profiles by typing it in your URL bar. Click on the Open Folder button under the Local Directory, not root. Then right click when inside the new profile folder and select paste. Then restart Firefox. You should now have all your previous bookmarks, and data back.

If this solved your problem, mark as solution.

Regards, Arman

@ARMAN KHAN - Thank you very much for your help but as I said in my post/question, no "Old Firefox Data" file has been created on the desktop. We cannot make a recover through this path.

Hi celine.ganty, if they haven't already, you should suggest to your friend to do a regular shutdown and restart of Windows to free up file locks, complete any pending updates, and hopefully resolve any confused permissions.

Inside Firefox:

Does the Restore menu show any bookmark backups available for restoration, or is this more like a new profile? Steps to access Restore: Restore bookmarks from backup or move them to another computer

Has your friend seen the ominous warning message described in this article: Fix "The bookmarks and history system will not be functional" error message?

On disk:

Does the currently live profile folder contain a file called logins.json-corrupt (or similar) or places.sqlite-corrupt?

Are there any unlisted profile folders? What I mean is, if you open this folder, can you see any additional folders that are not listed on the about:profiles page:

%APPDATA%\Mozilla\Firefox\Profiles

Hello again, celine.ganty,

Sorry for previous answer, First, Firefox automatically creates backups of your bookmarks, which can be helpful if your bookmarks are lost or missing.

Click the Bookmarks button Bookmarks-29 (or New Fx Menu > Bookmarks) and select Show All Bookmarks. At the top of the Library window, click on Import and Backup and select Restore. Click the date of the bookmark backup you want to recover. In the new window that appears, click OK. Your bookmarks from the selected date should now be restored. For more information, see the Restore bookmarks from backup or move them to another computer article. For other solutions, see the Recover lost or missing Bookmarks article.

If the above doesn't work, it could be that a file got corrupted (namely the places.sqlite file). You can install the Places Maintenance extension to run maintenance on the file. Please read the following articles first as they provide helpful hints and instructions that may be relevant to you:

http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file Did this fix your problems? Please report back to us!

Thank you.

@jscher2000 : thank you very much for your answer. To react to your suggestions:

• Restart of Windows had been tried already before posting this question ;
• There is no backup bookmarks available for restoration ;
• The ominous warning message suggested didn't appear ;
• There is, unfortunately no logins.json-corrupt or places.sqlite-corrupt file.

@ARMAN KHAN : thank you again for your help. As just said to jscher2000, no backup of bookmarks has been found. places.sqlite doesn't seem corrupted neither since the places.sqlite-corrupt hasn't been found.

@jscher2000 and @ARMAN KHAN : I think the passwords and bookmarks are definitely lost. Profile has been erased. Moreover, Firefox crashed this morning again and came back "by itself" to previous 76 version. We thus got the attached error message (in french, sorry) which was normal for the current situation (version 76 instead of 77) but which was the same that appeared when updating to version 77.0.1 !

We think there is nothing to do about it unfortunately. However, if this problem is linked to this new version of Firefox, we just wanted to warn the support about it.

Thank you again for your help.