To perform this procedure, the account you use must be delegated the Exchange Organization Administrator role.

For more information about permissions, delegating roles, and the rights that are required to administer Exchange 2007, see Permission Considerations.

Also, before you perform these procedures, confirm that you have enabled Exchange ActiveSync on the Exchange 2007 server that has the Client Access server role installed.

Note:
By default, Exchange ActiveSync is enabled on a Client Access server.

 To enable a user for Exchange ActiveSync using the Exchange Management Console

1. Open the Exchange Management Console.

2. Under Recipient Configuration, select Mailbox.

3. Select Properties from the action pane or right-click the user's mailbox, and then click Properties.

4. Click the Mailbox Features tab.

5. Select Exchange ActiveSync, and then click Enable.

6. Click OK.

 To enable a user for Exchange ActiveSync using the Exchange Management Shell

• Run the following command:

  Set-CASMailbox -Identity <SMTP Address of user> -ActiveSyncEnabled $true

For more information about syntax and parameters, see Set-CASMailbox.

• For more information about the Exchange Management Shell, see Exchange Management Shell (SP1 and SP2).
  
• For information about how to disable a user for Exchange ActiveSync, see How to Disable Exchange ActiveSync for a User.