Click the flyout on the favorites palette and choose "Load Favorites". Navigate to the favorites file you want. We keep general favorites at 3 Resources : Favorites.
If you already have favorites in the list, you will be asked if you want to Merge or Replace the existing favorites. Unfortunately, "Replace" refers to the list as a whole: All the current favorites will be deleted. To overwrite current favorites with those in the new file, while leaving the others alone, you need to choose "Merge." This has its own quirk: When a matching name is found, you will be offered the options "Skip" (don't overwrite), "Skip All" (which cancels all remaining overwrites), and "Overwrite". There is no "Overwrite All", so in order to accept all the incoming favorites, you have to click "Overwrite" however many times. Another D-minus interface element.
Also, I can't stand the word "favorites". It means I have a great subjective, emotional, aesthetic interest in the item, much greater than in most items. "OMG, I loooooove this 2x4 wall!!!" No. They should be called presets.