1. Select File | Import and Export... from the menu.
2. Make sure Export to a file is highlighted.
3. Click Next >.
4. Now make sure Comma Separated Values (Windows) is selected.
5. Click Next > again.
6. Highlight the Contacts folder.
7. Click Next >.
8. Use the Browse... button to specify a location and file name for the exported contacts. Something like "Outlook.csv" or "ol-contacts.csv" on your Desktop should work fine.
9. Click Next > (once more).
10. Now click Finish.

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