Always launches with the profile selector. Then install a profile switcher extension. Done.
Unfortuntaley 1) it doesn’t really come out of the box, though and 2) the extension must be installed on every single profile. Not the most obvious or user friendly.
I just launch Firefox with this option:
"C:\Program Files\Mozilla Firefox\firefox.exe" -ProfileManagerAlways launches with the profile selector. Then install a profile switcher extension. Done.
Unfortuntaley 1) it doesn’t really come out of the box, though and 2) the extension must be installed on every single profile. Not the most obvious or user friendly.