Contacts sidebar

The Contacts sidebar lists available groups, folders (if you use an Exchange account in Contacts), and network directory services.

Show or hide the sidebar: Choose View > Show Groups or View > Hide Groups. Or drag the left or right edge of the Contacts window.
Resize the sidebar: Drag the sidebar’s separator left or right. If you drag it all the way to the left, the sidebar is hidden.

If you don’t see expected groups, folders, or directories in the sidebar, choose Contacts > Preferences, click Accounts, then make sure your accounts are enabled.