Bookdog registers with the Mac OS to open .plist, .html and .sqlite files because some users have requested the ability to open bookmarks files with these extensions. Unfortunately, these file extensions are used for other types of files besides bookmarks, and Bookdog will only succeed in opening such a file if it is a bookmarks file.
If you have have installed another application which properly opens one of these file types, you will want the system to give these files to this other application instead of Bookdog when you doubleclick on them.
If your system has Bookdog trying to open these files, you need to change your system's preference for opening such files:
1. Select one of the files with the problem extension in any Finder window.
2. In the Finder's "File" menu click "Get Info".
3. In the Info window which appears, near the bottom, in the "Open with" section
popup menu, select the application that you really want to open files with this
extension.
4. Click the "Change All" button.