Your Outlook version is relevant here, not your OS.
The connection that permits the Outlook Address Book to display the
contents of your Contacts Folder is fragile and easily corrupted. There
are 2 key components for the Outlook Address Book to work. First, the
Outlook Address Book Service must exist in the Outlook Profile. Second,
any Contacts Folder you want it to display must be enabled as an "email
address book" in its properties.
It is not unusual for the Outlook Address Book to “lose track†of this
connection to its Contacts Folder when you move your data file, update
your Outlook version or update your operating system. It may also retain
outdated links to Contact Folders that it can no longer find whereupon
it will display the alarming but unhelpful message the "Contacts Folder
is no longer available and cannot be displayed." The steps to repair or
reset this connection differ with each version. Sometimes brute force is
required to correct the settings by removing the Outlook Address Book
service completely from the Outlook Profile, closing Outlook, and then
re-adding it.
No further instructions are possible without knowing your Outlook
version. You can probably take it from here.
