This can be 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
• http://kb.mozillazine.org/Bookmarks_not_saved

Do you mean names and passwords in the Password Manager or do you mean that you are no longer logged on to (remembered by) websites after closing and restarting Firefox?

If the latter happens then you have a problem with cookies that are not kept or the file that stores the cookies is corrupted.

• http://kb.mozillazine.org/Websites_report_cookies_are_disabled (Other Solutions)

If Firefox doesn't offer to store passwords in the Password Manager then check that you aren't running Firefox in Private Browsing - Use Firefox without saving history mode.

Do not use Delete browsing, search and download history on Firefox to clear the "Cookies" and the "Site Preferences"
Clearing "Site Preferences" clears all exceptions for cookies, images, pop-up windows, software installation, and passwords.

• http://kb.mozillazine.org/Cookies

Thanks for your response mate.

As far as loosing the bookmarks, I deleted places.sqlite and let the firefox create a new one. This solved the problem for about 3 days and then again I started loosing my bookmarks (and also some of the history). is that usual ??

Any other suggestions anyone?

Did you update to Firefox 4.0.1 ?

If you did then it is possible that it was related to that update and that you may need to repeat those steps.

I have followed all the suggestions. I deleted places.sqlite and let the firefox create a new one. I have not used clear history or any other software to clear history. this is what happens. I bookmark a page. I check and it is there. I close Firefox 4 and start is again and the bookmark is not there. The Firefox closes normally (doesn't crash or anything). Also most of the history (the sites I visited) is not being kept in history area. Any other suggestions would be greatly appreciated.