The Exchange 2010 SP1 mailbox role install fails, but the mailbox server role server does install with a mounted database, which contains (4) system/arbitration mailboxes. EXBPA reports that the mailbox server has a failed install. I have followed the procedures in various blogs to disable IPV6, use IPV6, run setup/prepare AD again, obviously each time to remove the mailbox role and re-install I have to disable the mailboxes in that database, to allow the mailbox server role removal, which it successfully does. The Exchange 2010 CAS servers installed with no issues. The forest is a single domain model. There is a valid and required AD trust to another domain. The existing Exchange Org has Exchange 2003 MBS, Exchange 2007 CAS/HT/MBS , Exchange 2010 SP1 CAS/HT servers The Exchange 2010 servers are VMware servers, Windows 2008R2 The Exchange 2010 securtiy groups exist Error: Event ID 1002 Providor Name:MSExchangeSeup "Couldn't resolve the user or group /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. The trust relationship between the primary domain and the trusted domain failed" Any assistance will be greatly appreciated. thanks QAlexis75

would you copy and paste the contents of <system drive>\ExchangeSetupLogs\ExchangeSetup.log hereMCP, MCSE 2000 , MCSA 2000 ,MCSA 2003 , MCITP , MCTS , MCT

Dear Qalexis75, had the same problem, found soulution that worked. http://www.msdigest.net/2010/11/sp1-install-fails-with-couldnt-resolve-the-user-or-group-mydomain-localmicrosoft-exchange-security-groupsdiscovery-management/ Jerry Zak, Prague

Mohamed, I am unable to paste the error log, ad it seems too large. thanks QQAlexis75

Send it by mail on Mohamed.dawy@hotmail.comMCP, MCSE 2000 , MCSA 2000 ,MCSA 2003 , MCITP , MCTS , MCT

Jerry Zak, Thanks for your reply, but the post suggests :- 1.delete discovery mailbox 2.install SP1 (the missing mailbox role) 3.then recreate the discovery search mailbox manually 4.add permissions to the discovery search mailbox I have to delete the diacovery search mailbox before I can remove to mailbox server role from the server to allow me to re-run the mailbox server role install. I thought the the install of the mailbox server role created the discovery search mailbox on the database which gets created during the install, so how can I recreate the discovery search mailbox after the install of the mailbox server role, which partially fails? (see point 2 above) thanks Q QAlexis75

the same error was returned when getting the mailbox permissions for the user/mailbox. Removing the AD trust resolved the issue thanks for your assistance all those who replied. thanks Q QAlexis75