1. Open SysTools DBX Converter tool. Go to Start » Programs » SysTools DBX Converter » SysTools DBX Converter. Software will display the initial screen as follows:
2.Choose Outlook Express DBX files to convert DBX to PST or EML or MSG or RTF format. To select DBX files, click the “Add” button as shown below in the red marked area:
3. After clicking the Add button, choose a DBX file, that you wish to convert, as shown in the following screen:
4. Select the DBX File and Click the "Open" button. For selecting another DBX file, repeat the same step as above. After you select a number of DBX files, they will be listed as shown under: 
5. Click the “Browse” button to select a location for saving the converted files (you can convert to PST or EML or MSG or RTF).
After clicking the Browse button, you see the following window:
6. Choose a desired location. Then, click the “OK” button. Software will display the following screen: 
7. Select a format from the Save Options given. You can convert DBX files in any of the four formats (EML, PST, MSG, & RTF) as shown under:

9. After you choose a Save Option, following screen appears:
10. Click the “Convert” button to start the conversion process. Software shows on-screen progress detail as shown below:
