I'm afraid that firefox does not keep a backup of history files, if it looks like they've been cleared, then there isn't any (easy) way of getting them back :(

Could you check your history settings, and have you updated firefox today/yesterday? (4.0.1 was pushed) - That may of caused it?

Thank you for your quick response! It looks like 4.0.1 is what did it. Is this going to happen every time a new Firefox release is installed? That doesn't make sense, but if it's true, it kinda makes me want to go back to IE. Update installs should at the very least retain the prior history.

I'm not entirely sure, it's not done so in the past, so this was either a one-time issue with the update (of which there a few, they just tend to pop up when rolling out a large update - it's nowhere near ideal :( ).

OK. Thanks again. I'll make a suggestion for the next update that they ensure the history is not overwritten.

If I've answered this question, could you mark this question as solved/"choose my solution"?

Helps keep the place tidy ;) :)

The Firefox 4.0.1 update was released on April 28th, so unless that PC wasn't used for like the last 6 weeks that update didn't cause that loss of browsing history.

Then the 4.01 upgrade was not the reason for the history disappearing, because I was using the PC daily. Do you have a guess as to what may have caused it?

Did you ever use Private Browsing or use Clear Recent History ?

• https://support.mozilla.com/kb/Private+Browsing
• https://support.mozilla.com/kb/Clear+Recent+History

This can also cause by a problem with the file places.sqlite that stores the bookmarks and the history.

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

If you want to preserve visited sites then you can consider to bookmark them with a click on the star at the right end of the location bar or do a copy and paste in the Bookmarks Manager (Library) from the history to a bookmarks folder.