Mail unable to find contacts

Question

When using Mail to compose an Email, I am unable to find any contacts listed. The ICloud is active and required Email addresses are shown in Contacts but they do not appear nor can be found in Mail.
Any suggestions would be gratefully received.

Answer 1

From the Mail menu bar, select
Mail ▹ Preferences ▹ Composing
and check the box marked
Automatically complete addresses
You don't have to configure LDAP. If the box is already checked, or if checking it has no effect, then continue as below.
Please follow these directions to delete the Mail "sandbox" folder.
Back up all data.
Triple-click anywhere in the line below on this page to select it:
~/Library/Containers/com.apple.mail
Right-click or control-click the highlighted line and select
Services ▹ Reveal
from the contextual menu.* A Finder window should open with a folder named "com.apple.mail" selected. If it does, move the selected folder — not just its contents — to the Desktop. Leave the Finder window open for now.
Log out and log back in. Launch Mail and test. If the problem is resolved, you may have to recreate some of your Mail settings. You can then delete the folder you moved and close the Finder window. If you still have the problem, quit Mail again and put the folder back where it was, overwriting the one that may have been created in its place. Post your results.
Caution: If you change any of the contents of the sandbox, but leave the folder itself in place, Mail may crash or not launch at all. Deleting the whole sandbox will cause it to be rebuilt automatically.
*If you don't see the contextual menu item, copy the selected text to the Clipboard (command-C). In the Finder, select
Go ▹ Go to Folder...
from the menu bar, paste into the box that opens (command-V). You won't see what you pasted because a line break is included. Press return.