[Brian]

This sounds like we're having trouble getting the list of calendars from the Sync Services database.

Please contact the support ninjas at omnifocus@omnigroup.com and we'll try to get this straightened out.

It would be helpful you included any error messages that appear on the console when you try to open the preferences pane.

To do this, you'll want to open up the utilities folder (inside your Applications folder) and launch the app named "Console". Press the "clear display" button in the toolbar, then launch OmniFocus and open that preferences pane.

If any text appears in the console window while this is happening, please copy and paste it into an email to that address I linked above.