Make sure that you do not run Firefox in (permanent) Private Browsing mode.

• https://support.mozilla.org/kb/Private+Browsing

• Tools > Options > Privacy: Use custom settings for history
• Deselect: [ ] "Always use private browsing mode"

See also:

• http://kb.mozillazine.org/Session_Restore
• https://support.mozilla.org/kb/Session+Restore

You can also check these prefs on the about:config page.

• http://kb.mozillazine.org/browser.sessionstore.max_tabs_undo
• http://kb.mozillazine.org/browser.sessionstore.max_windows_undo
• http://kb.mozillazine.org/browser.sessionstore.resume_from_crash

Thx, Cor-el, but sorry, I need help in finding "Tools", but just under "Options", I can't find the option you're referring to...in the Firefox button, there is "start private browsing" - is this what you're referring to? - I didn't activate this deliberately.

Addendum: Thx again, Cor-el...have tried several of your links; somehow, some of my tabs have returned, yay! But today, for the first time, some previous tabs have "retreated" to the background (gone "blurry"), and cannot be accessed again.

If you care to respond, thanks again from a barely pc-literate person!

I did not find any of the above answers as actually a solution for the problem of : how to restore all the history tabs which I cleared since one week ago? so, they are disappearing now , if there is no way to restore them ........please tell us, here, or replying me with an Email , thanks,

Hi muradmourid, you may be referring to two different things --

• Session information (windows and tabs open in your last session)
• History (URLs listed under History > Show All History)

Session information is only stored until you restart Firefox, and after you restart Firefox, it's replaced with the new information. This could be very difficult to recover.

History is stored together with cookies in the places.sqlite database. Databases generally do not have any undo function, particularly if you have closed Firefox during the past week. Depending on your OS, there may be "shadow copies" of places.sqlite, but rolling the file back would lose recent data.

Does that sound like it addresses your question? If not, please explain what's happening in more detail.