Sync your Yahoo and Outlook contacts with Microsoft Outlook to save both in one location and to access your Yahoo contacts from all Outlook email accounts. Sync the contacts by exporting them from Yahoo as a CSV file, and then importing them into Outlook by using the Import/Export wizard. You have the option to update existing contacts when importing to Outlook or to ignore duplicate contacts.
Exporting the Contacts From Yahoo
Log in to Yahoo Mail and then click the Contacts button to view all your contacts. Select the contacts you wish to export by checking their boxes; all contacts are exported by default if you don't check any boxes.
Click the Actions button and select Export from the menu to display the Export Contacts dialog.
The Microsoft Outlook options is selected by default; click Microsoft Outlook if it is not. Click the Export Now button to export the selected contacts in a CSV file.
Save the CSV file on your hard drive. Storing it on the desktop is helpful for easy access to the file.
Importing the CSV File into Outlook
Open Microsoft Outlook, click File and select Open and Export. Click the Import/Export button in the right pane to open the Import and Export Wizard dialog.
Select Import From Another Program or File and click Next.
Select the Comma Separated Values option and click Next.
Click the Browse button and then select the CSV file you downloaded from Yahoo.
Select the Replace Duplicates With Items Imported if you want to replace Outlook contacts with Yahoo contacts for any contacts that exist in both accounts. To avoid overwriting contacts, select the Do Not Import Duplicate Items option. Click Next.
Select the Contacts (This Computer Only) option to store the contacts locally and then click Next.
Click Finish to start importing the contacts from the Yahoo CSV into Outlook's Contacts folder. The process usually takes less than a minute, depending on the number of contacts in the CSV file.