Update Rollup 3 for Exchange Server 2010 SP1 and Exchange Server 2007 SP3 has been released. An overview of the fixes can be found here:
http://msexchangeteam.com/archive/2011/03/08/458566.aspx
and the download here:
The installation of the rollup took about 20 minutes on my test system (Dual Core Xeon, 8 GB RAM, 2 x RAID1 15k rpm). The Exchange services are stopped during the installation, a restart of the server is not necessary.
