I have already: Ruled out fixes for very old Firefox versions, still online. Tried every preference, library, and bookmarking tool in menu. The three dots does not provide that choice. (It is the FIRST thing I tried.) Used the terminal to sudo apt-get purge Firefox and Used terminal to sudo apt install Firefox. Repeated above procedure after signing out, to stop any starless syncing. Signed back in. I had it when this computer was new, and I then installed Firefox, less than a year ago, Ubuntu canonical 20.04. Reinstalling should have the quick-bookmark star as I had when first installed. I have not: Selected "remove data from device". Next solution that actually works?