If you have groups within your system with contacts and you know that there are probably duplicates within other groups you can run a search using the Advanced Search area of the system to determine those in some but not in other groups and download the results into a spreadsheet.
E.g. I want to search for contacts/subscribers who are in Group A, but not in Group B.
Step 1. Under the Address Book select "Search & Segment Contacts" from the menu.
Step 2. Select the "Advanced Search" tab.
Step 3. On the right hand side of the screen you will need to remove the 'search conditions' by pressing the "x" icon.
The right hand side of your screen should now look empty like this image below.
Step 4. From the "Add Group Conditions" dropdown, select the first set of group(s) you want to search for users that are within this group. E.g Searching for users IN GROUP A.
Step 5. Click the "Add" button. Once you have done this the "Search Conditions" on the right hand side should be updated with this search query.
Step 6. You can make sure the group(s) you have selected have been added correctly by clicking on the dropdown menu under "Search Conditions".
Step 7. Then to select the other group(s) you want to search within you'll need to select the group(s) once again from the "Group Conditions" dropdown menu on the left of screen. E.g. Searching for uses who are NOT IN GROUP B. Select the "Add" button.
Step 8. The search query should then be added to the "Search Conditions" section on the right hand side. You will need to select "Not In" to change the parameters of the search.
Step 9. By default only Firstname, Surname and Email are exported in to the .CSV file, you need to select from the "Fields to Display" tab to ask the system to export more information if you require it.
Step 10. Selecting the additional information you want exported is done by selecting via tick box on all the information you need.
Step 11. Once you have selected the information you need you can click 'Search'.
Step 12. The results will be displayed in a list for you, this list may have many pages depending on how many users/subscribers are in your groups.
Step 13. Click "Export All to CSV" to download the data to a .CSV file.
Step 14. A pop up window will display so that you may name the file that will be exported. Once you have entered the name of the file, press "OK".
Step 15. You'll be automatically directed to the Export Results screen, here you can see all exports from the system over time. Click on the "download" icon on the left to download a copy of your file.