Make sure that you do not use Clear Recent History to clear the Browsing History when you close Firefox.

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

I don't clear my history at all, not browsing history or recent history.

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

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

You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"

To see all History and Cookie settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history

• Deselect: [ ] "Always use private browsing mode"

If you use cleanup software like CCleaner then check the settings for the Firefox application.

Been there, done that. I have checked settings, re-installed, disabled add-ons, and checked the settings of all of my utilities.

Now the damned thing is deleting history while I am still on and surfing!! Perhaps time to switch to chrome?

A possible cause is 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
• https://support.mozilla.com/kb/Bookmarks+not+saved#w_places-database-file

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.com/kb/Basic+Troubleshooting#w_8-make-a-new-profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

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