In MS Exchange Server 2010, if you have Short Message Service (SMS) message that have empty To or from fields on the the device, when you try to synchronize the device with the mailbox, the following error is logged in the Application log on the Client Access Server :
Time: <var>Time</var> ID: 4999 Level: Error Source: MSExchange Common Machine: <var>Computer</var> Message: Watson report about to be sent for process id: <var>Process ID</var>, with parameters: E12, <var>Build Type</var>, <var>Version Number</var>, AirSync, MSExchange ActiveSync, Microsoft.Exchange.AirSync.SchemaConverter .Common.EmailAddressConverter.CreateParticipant, UnexpectedCondition:ArgumentNullException, 0, <var>Version Number</var>. ErrorReportingEnabled: False
An ArgumentNullException exception is thrown and the sync fails because Exchange ActiveSync does not handle the empty To and Form correctly during the synchronization.
To fix this issue, you should install this update : 2803727