1. Open Outlook 2010 and click File > Options.
     
  2. When the Outlook Options window opens, click Advanced. In the right pane, click the Export button.
     
  3. In the Import and Export Wizard, select the Export to a file option, then click Next.
     
  4. Under Create a file of type:, select the Comma Separated Values (Windows) option to create a CSV file.
     

  5. Under Select folder to export from:, select the Contacts folder you would like to export, then click Next to continue.

     
  6. Under Save exported file as, click Browse to select a destination folder.

     
  7. In the File name: box, type a descriptive name for your contacts file, then click OK.

     
  8. Click Next.

     
  9. Complete the process by clicking Finish.

     

You have now exported your Contacts to a file that will allow you to migrate your Address Book into another email client.