Error when upgrading to SP2 (exchange 2010 SP1) hope this help someone

I had this error during update

Summary: 16 item(s). 13 succeeded, 1 failed.
Elapsed time: 00:45:52
Organization Preparation
Completed
Elapsed Time: 00:04:53
Preparing Setup
Completed
Elapsed Time: 00:00:02
Stopping Services
Completed
Elapsed Time: 00:04:15
Languages
Completed
Elapsed Time: 00:00:00
Remove Exchange Files
Completed
Elapsed Time: 00:01:35
Preparing Files
Completed
Elapsed Time: 00:00:04
Copy Exchange Files
Completed
Elapsed Time: 00:01:27
Language Files
Completed
Elapsed Time: 00:08:05
Restoring services
Completed
Elapsed Time: 00:00:08
Languages
Completed
Elapsed Time: 00:06:11
Hub Transport Role
Completed
Elapsed Time: 00:05:46
Client Access Role
Completed
Elapsed Time: 00:04:34
Unified Messaging Role
Completed
Elapsed Time: 00:03:04
Mailbox Role
Failed
Error:
The following error was generated when "$error.Clear();
          $name = [Microsoft.Exchange.Management.RecipientTasks.EnableMailbox]::DiscoveryMailboxUniqueName;
          $dispname = [Microsoft.Exchange.Management.RecipientTasks.EnableMailbox]::DiscoveryMailboxDisplayName;
          $dismbx = get-mailbox -Filter {name -eq $name} -IgnoreDefaultScope -resultSize 1;
          if( $dismbx -ne $null)
          {
            $srvname = $dismbx.ServerName;
            if( $dismbx.Database -ne $null -and $RoleFqdnOrName -like "$srvname.*" )
            {
              Write-ExchangeSetupLog -info "Setup DiscoverySearchMailbox Permission.";
              $mountedMdb = get-mailboxdatabase $dismbx.Database -status | where { $_.Mounted -eq $true };
              if( $mountedMdb -eq $null )
              {
                Write-ExchangeSetupLog -info "Mounting database before stamp DiscoverySearchMailbox Permission...";
                mount-database $dismbx.Database;
              }

              $mountedMdb = get-mailboxdatabase $dismbx.Database -status | where { $_.Mounted -eq $true };
              if( $mountedMdb -ne $null )
              {
                $dmRoleGroupGuid = [Microsoft.Exchange.Data.Directory.Management.RoleGroup]::DiscoveryManagementWkGuid;
                $dmRoleGroup = Get-RoleGroup -Identity $dmRoleGroupGuid -DomainController $RoleDomainController -ErrorAction:SilentlyContinue;
                if( $dmRoleGroup -ne $null )
                {
                  Add-MailboxPermission $dismbx -User $dmRoleGroup.Identity -AccessRights FullAccess -DomainController $RoleDomainController -WarningAction SilentlyContinue;
                }
              }
            }
          }
        " was run: "Couldn't resolve the user or group "mucicco.local/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.".

Couldn't resolve the user or group "mucicco.local/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.

Click here for help... http://technet.microsoft.com/en-US/library/ms.exch.err.default(EXCHG.141).aspx?v=14.2.247.1&e=ms.exch.err.Ex88D115&l=0&cl=cp

Elapsed Time: 00:05:42
Management Tools
Cancelled
Finalizing Setup
Cancelled

So after searching for solution i fund something about Discovery search mailbox problems

Note: my Discovery Search Mailbox was disabled in OU i have seen this when i ran to a problem so i dont know will it be like that in your case, some suggest disabling Discovery Search Mailbox.

And i opened AD users and computers go to users OU and DELETED Discovery Search Mailbox, after that i run setup again and no problems it finished ok, i tested everything and server is working like it supposed to.

Hope this Helps someone, i know its not pleasant to go whit something you expect to go like charm and end up with not working server...

Thx...