In most cases it is the corrupted Navigation Pane settings file that prevents Outlook from starting successfully, so the first thing you need to do is to mend it. Here's how you can do this on different operating systems:
1. If you use Vista, Windows 7 or Windows 8, click the Start button. On Windows XP, click Start > Run.
2. Type the following command in the search field:
outlook.exe /resetnavpane
Note: Be sure to enter a space between outlook.exe and /resetnavpane.
3. Press Enter or click on the file in order to reset the Navigation Pane settings and then open Outlook.
Or try to repair your outlook.pst file using
Outlook Fix Toolbox
