Hello, During the installation of Exchange 2010 SP2 mailbox role, I received an error "Could not resolve the user or group <mydomain> / Microsoft Exchange Security Groups / Discovery Management". I found a solution and applied it.It rely on disabling box DiscoverySearchMailbox rerun setup process and enabling mailbox again .I've already installed two CAS/HT Exchange 2010 sp2 without any problems. I would like to know what is the cause of this problem and how to check health of my organization before upgrade process. My environment is Exchange Exchange 2007 SP3, which was previously upgraded from Exchange 2003. Regards, Pawel

Check your setup log for more info, also I'd run the ExchBPA and give it a check. check your event logs for any errors. I assume SP2 has now been installed without issues?>Sukh

Hi, I'm installing Exchange 2010 with SP2, there is no additional upgrade process. I've Exchange 2007 SP3 infrastructure and I want to upgrade it to Exchange 2010 SP2 in one task. I've run prepeare/ps, prepare/p, prepare/pd whith no errors, I've also installed two CAS/HT 2010 SP2 with no errors. Only during instalation of MBx role I've got an error " Here is my setup log content: Processing object "zzzz/Users/DiscoverySearchMailbox {D919BA05-46A6-415f-80AD-7E09334BB852}". [12-16-2011 11:27:38.0748] [2] Checking if the specified user or group "zzzz/Microsoft Exchange Security Groups/Discovery Management" is a Security Identifier. [12-16-2011 11:27:38.0748] [2] Checking if the specified user or group "zzzz/Microsoft Exchange Security Groups/Discovery Management" is a SAM account or a foreign forest account. [12-16-2011 11:27:55.0055] [2] [ERROR] Unexpected Error [12-16-2011 11:27:55.0055] [2] [ERROR] Couldn't resolve the user or group "zzzz/Microsoft Exchange Security Groups/Discovery Management." If the user or group is a foreign forest principal, you must have either a two-way trust or an outgoing trust. [12-16-2011 11:27:55.0071] [2] [ERROR] The trust relationship between the primary domain and the trusted domain failed. I've one forest with one domain and one external trust with other company. When setup process has finished with this error I can open EMC and I can see new mailbox server and mailbox database. I found resolution here . I disabled mailbox DiscoverySearchMailbox and run setup process again, it finished without any errors, but for me it's very important to find what cause this problem. Regards, Pawel

Hi Pawel, Base on my research "DiscoverySearchMailbox" is disabled by default. Just from my perspective the problem might be caused by there's old trusted relationship. Rowen TechNet Community Support