Quite a few people have reported errors after installing SP2 have a read of the comments on this blog http://blogs.technet.com/b/exchange/archive/2011/12/05/released-exchange-server-2010-sp2.aspx before deciding whether to upgrade.
- Exchange SP2 makes numerous schema updates so the account you use to update must have schema admin rights. Once the schema has been updated wait for active directory replication to update the entire forest.
- Please follow the normal upgrade process of CAS, Hub Transport then Mailbox servers. You can update Edge servers either first or last. Also UM servers should be updated before mailbox servers.
- I recommend running windows update (with extra MS updates) on the exchange 2010 server
- Office 2010 filter packs http://go.microsoft.com/fwlink/?LinkID=191548 you will want the 64 bit version.
- IIS6 WMI compatibility component this can be added from server manager see below.
- Download and run the sp2 install. It will check if any pre-requisites are missing.