If Firefox switches to "Remember History" then that means that all history settings are the default and that cookies are enabled.

Firefox shows the "(Never) Remember history" choice if all the history and cookie setting are the default. Make at least one change to the default setting if you want "Use custom settings for history" to stay selected. Otherwise Firefox will revert to "(Never) Remember history" if you return to the Privacy tab. The choice "Use custom settings for history" will stay selected as long as not all settings are the default to make you aware that you made changes.

What kind of problems do you have?

If clearing the cookies doesn't help then it is possible that the file cookies.sqlite that stores the cookies is corrupted.
Rename (or delete) cookies.sqlite and cookies.txt, if they exist, in the Profile Folder in case cookies.sqlite got corrupted.

• http://kb.mozillazine.org/Cookies#Removing_cookies

Thanks for your help! The original problem was that an online learning program was not working and their support told me to make sure I had Java and allowed cookies (and popups). It was when checking prefs that I found the inability to keep pref change on privacy. Thus my query. Your answer made so much sense that I fooled around to make a small change to test it, then I still could not use the program (it was not remembering my work). I decided the cookies splite (or whatever) was probably corrupted and just decided to delete the whole thing (ff 3.6.13) and re-install. Dramatic, but effective! Now works (I was totally aggravated by the time I got to this point). Now I need to move my more valuable bookmarks from the very helpful Google Chrome... Thanks!

I followed cor-el advice on getting the custom settings to stay on firefox and it worked.

Thanks cor-el!

Thanks, Cnon