SYMPTOMS
If you are using a Microsoft Outlook client computer, you cannot download an offline Address Book. When you try to download an Address Book in Outlook, the following error is logged in the synchronization log:
7:59:00 Microsoft Exchange offline address book
7:59:00 0X80004005

CAUSE
This issue may occur if the mailbox store has not been associated with a valid offline Address Book.

RESOLUTION
To resolve this issue, follow these steps:
1. Start Exchange System Manager.
2. Expand Organization, and then expand Administrative Groups.

If "Administrative Groups" does not appear under Organization, make sure that you have configured Exchange System Manager to display Administrative Groups. To do so, right-click Organization, click Properties, and then click Display administrative groups.
3. Expand the administrative group to which the server belongs.
4. Expand Servers, expand the server that you want to configure, and then expand First Storage Group.
5. Right-click Mailbox Store, and then click Properties.
6. In the Offline Address Book section, make sure that a valid offline Address Book is listed.

If one is not listed, click Browse, and then click a valid offline Address Book. You can use Default Offline Address Book as the default setting.