Symptoms
In a Microsoft Exchange Server 2013 environment, Exchange shadow Offline Address Book (OAB) downloads don't complete successfully. Additionally, in the event log, you will receive a warning with Event ID 104 that resembles the following:
Resolution
To fix this issue, install Cumulative Update 15 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
References
Learn about the terminology that Microsoft uses to describe software updates.