I notice you have a user.js file to initialize prefs each time you start Firefox: UserJS.exists: TRUE.

Did you create this file yourself ?

Detail like websites remembering you (log you in automatically) is stored in a cookie.

You can use these steps to make a website recognize and remember you:

• create a cookie allow exception with the proper protocol (https:// or http://) to make a website remember you

You can check that you aren't clearing important cookies.

• using "Delete cookies and site data when Firefox is closed" keeps cookies with an allow exception
• using "Clear history when Firefox closes" to clear cookies clears all cookies including cookies with an allow exception you may want to keep

• Options/Preferences -> Privacy & Security
  Cookies and Site Data: "Manage Exceptions/Permissions"

cor-el ==>Thanks for the suggestions.

I've just re-installed Firefox 84.0.2 with a new profile and imported/synced all my information... This new instance now keeps me logged into Dashlane when I exit and relaunch. No idea what the problem was previously but now I'm ok.

Previous Response.... I did not knowingly create a user.js file. Should I delete it? "Delete cookies and site data when Firefox is closed" is not selected. "www.dashlane.com" is already an exception to cookies and site data. Any additional ideas/suggestions much appreciated!