thank you for the clarification but still if I try to log in into Firefox (for example) as soon as I type "c", then the suggestion "[email protected]" comes out. Is that a memory or history? How can I delete all the suggestions? My request is because if a colleague of mine, use my computer, I really wish not to discover that I have already registered at "Mozilla Support". Please understand that I am taking it to the extreme for finding the real issue. Thank you again, I really wish you could help me to find out the solution which was already into the previous version of "Mozilla Firefox"

After typing the "c", press the down arrow so "[email protected]" is highlighted, then press "Del" on your keyboard so it is removed from the suggestions.

Let us know if that solves your concern.