If you are synchronizing your BlackBerry with different personal information manager (i.e. Outlook and Lotus Notes) or if you are synchronizing your data with Google Sync it can –admittedly rarely – happen that you screw up your contacts database on your BlackBerry. You might end up with duplicates, deleted address field, sorting of contacts messed up.

In case you want to delete you contacts database and do not want to delete each contact indivudally you can your BlackBerry Desktop Manager to clear your contact database.

1. Open Desktop Manager and select Backup and Restore.
2. In the window that opened you have to click on “Advanced”.
3. Select "Address Book" in the "Device Database" list on the right side of the screen and press the Clear button.

This way you can delete your contacts database while leaving your calendar and notes untouched on the BlackBerry.