Update Rollup 2 for Exchange Server 2010 Service Pack 3 (SP3) resolves issues that were found in Exchange Server 2010 SP3 RU1 since the software was released. This update rollup is highly recommended for all Exchange Server 2010 SP3 customers.
For a list of changes that are included in this update rollup, see KB2866475.
This update rollup does not apply to Exchange Server 2010 Release To Manufacturing (RTM), Exchange Server 2010 Service Pack 1 (SP1) or Exchange Server 2010 Service Pack 2 (SP2).
For a list of update rollups applicable to Exchange Server 2010 RTM , Exchange Server 2010 Service Pack 1 (SP1) or Exchange Server 2010 Service Pack 2 (SP2), refer to the Knowledge Base article KB937052.
Download it here:http://www.microsoft.com/en-us/download/details.aspx?id=39835
Cheers,
Anderson Patricio
http://www.msexchange.org/blogs/patricio/
http://www.andersonpatricio.ca
Twitter: @apatricio