If you are using Firefox and have separators (horizontal lines) between bookmarks in certain positions, Bookdog 4.2.14 may write your Firefox file with identifiers, and this causes Firefox to hang upon launch and need to be force-quit.
To solve this problem, please launch Bookdog, click menu > Bookdog > Check For Update and update to Bookdog 4.2.15 or later.
After the update launches, open your Firefox bookmarks once (in the usual way, by clicking in the menu File > My Mac Account > Firefox. If Bookdog found and corrected errors, it will "bark" once through your Mac's speakers. (If Bookdog does not bark, you were not affected.)
After this, Firefox should launch properly. Sorry about the trouble!