This policy setting allows you to set whether users will be prompted to migrate the Personal Address Book (PAB) contents into a Contacts folder they choose when Outlook first starts. PAB is not supported in Outlook.
If you enable this policy setting, users will not be prompted to migrate PAB contents. You can choose to:
1.) Migrate users' PAB contents automatically to the Contacts folder (the default Outlook Address Book) when Outlook first starts (silent migration) and remove the PAB from users' profiles.
2.) Remove the PAB from users' profiles. Removing the PAB from profiles does not delete the PAB files; they can be imported later using Import and Export.
If you disable or do not configure this policy setting, users will be prompted to migrate PAB contents.