What exactly did you use, full name and version with links to support or the home site would help.

I guess it was intended to be erased permanently. You should really try to rely on bookmarks a bit more so that you can keep track of things. Sesionrestore that keeps open tabs is a bit fragile, History is good but not backed up at all by Firefox itself.

You did not give any system information.

Forum Note
Is that a result of an aaq workflow change. I hope not but it was proposed/planned

You would need an older backup copy of the sessionstore.js file recover those lost tabs.

You can try to restore a previous version of the sessionstore.js file.

• Right-click: Properties > Previous Versions

• http://windows.microsoft.com/en-US/windows7/Previous-versions-of-files-frequently-asked-questions

i used Tracks Eraser Pro v8 http://www.acesoft.net/download.htm

and i use the latest version of Firefox v 26 . i have windows 7 -- one more question : where do Firefox hide tabs sessions in windows? if it is in hiden temp folder then i guess it got deleted permanently

thanks for reply anyway

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

• http://kb.mozillazine.org/Profile_folder_-_Firefox

it seems to be they got deleted permanently

thanks anyway for the quick reply

Follow this article

https://support.mozilla.org/en-US/kb/how-do-i-restore-my-tabs-last-time?esab=a&s=restore+tabs&r=0&as=s

Thank you.

sultan1001
You said

it seems to be they got deleted permanently thanks anyway for the quick reply 

The answer you marked as a solution mentions sessionstore.js that and files with a similar name are used to store the open tabs.

The files are in the Firefox profile and this is normally a hidden set of folders and files. It is however often tracked by Windows previous versions and so possibly recoverable.

See also

• Profiles - Where Firefox stores your bookmarks, passwords and other user data
• http://kb.mozillazine.org/Show_hidden_files_and_folders
• http://kb.mozillazine.org/Sessionstore.js