On my 32-bit test environment with SP1 Beta 2 installed, upgrade to SP1 RTM fails with: Organization Preparation Failed Error: Active Directory operation failed on exchange.test.local. This error is not retriable. Additional information: An attempt was made to modify an object to include an attribute that is not legal for its class.Active directory response: 0000207D: UpdErr: DSID-03150F9C, problem 6002 (OBJ_CLASS_VIOLATION), data 0 An object class violation occurred. I also have OCS 2007 installed and combined with Exchange UM. Any hints? Thanks, Johann