Why does Permanent Private Browsing keep enabling itself?

Question

Every time I open Firefox, Permanent Private Browsing is enabled.
I tried to disable it manually countless times (by un-checking the box next to "always use private browsing mode" in the options window), but then I quit firefox and when I open it up again, there it is enabled again.
Please note that I mean PERMANENT mode, not the temporary option on the main menu.

Answer 1

How do I turn off Private Browsing?
* https://support.mozilla.com/en-US/kb/Private%20Browsing#w_how-do-i-turn-off-private-browsing
-> click '''Firefox''' button and click '''Options''' -> '''Privacy''' panel -> '''History''' section -> ''under'' '''Firefox will:''' ''select'' '''"Use Custom Settings for History"''' -> REMOVE Checkmark from '''Permanent Private Browsing mode'''
* place Checkmarks on 1) Remember my Browsing History 2) Remember Download History 3) Remember Search and Form History 4) Accept Cookies from sites -> 5) Accept Third-party Cookies -> ''under'' '''Keep Until :''' ''select'' '''They Expire'''
* REMOVE CHECKMARK from CLEAR HISTORY WHEN FIREFOX CLOSES
-> Click OK on Options window -> Restart Firefox
Check and tell if its working.
-> IF you use '''Clear Recent History''' feature, DO NOT select '''Cookies, Forms and Search History, Active Logins, Site Preferences'''
* https://support.mozilla.com/en-US/kb/Clear%20Recent%20History#w_what-things-are-included-in-my-history
-> IF you use Privacy Cleanup softwares like CCleaner etc., DON'T SELECT FIREFOX IN ITS SETTINGS. These softwares can be responsible for Deleting your Firefox Settings.