Firefox automatically makes a backup of the cookies file and does a fresh launch.
Every time I close firefox the cookies file in my profile folder "cookies.sqlite" makes a backup of itself "cookies.sqlite.bak" so when I open firefox again I start out fresh unless I change name of the file back to what it supposed to be then I could launch firefox back with the old cookies with no visible issues.
So, how do I make it so the firefox doesn't automatically make a backup of my old cookies and replace it a new file?
Firefox normally doesn't create such a .bak file, so it is possible that other (security) software keeps an handle on the cookies.sqlite file and prevents Firefox from removing the renamed file.
So you need to make sure your security software doesn't interfere with files in the Firefox profile folder.