To resolve this behavior, assign the appropriate Active Directory Read / List permissions to the Change Auditor user account being used to log into the Client.
If the permissions already exist but the OU is still not being displayed, ensure the Client connection profile does not have credentials saved for a different user account. More details on correcting this can be found in the following Knowledge Base article:
Client Connection Profile opens client using a different user account from the logon user: https://support.quest.com/kb/205312