Error trying to install CU2 on the Mailbox Server.  Any ideas?  I was running CU1.  

Error:
The following error was generated when "$error.Clear(); 
            if ($RoleIsDatacenter -ne $true -and $RoleIsDatacenterDedicated -ne $true)
            {
            if (Test-ExchangeServersWriteAccess -DomainController $RoleDomainController -ErrorAction SilentlyContinue)
            {
            $sysMbx = $null;
            $name = "SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}";
            $dispName = "Microsoft Exchange";
            Write-ExchangeSetupLog -Info ("Retrieving mailboxes with Name=$name.");
            $mbxs = @(Get-Mailbox -Arbitration -Filter {name -eq $name} -IgnoreDefaultScope -ResultSize 1 );
            if ($mbxs.Length -eq 0)
            {
            Write-ExchangeSetupLog -Info ("Retrieving mailbox databases on Server=$RoleFqdnOrName.");
            $dbs = @(Get-MailboxDatabase -Server:$RoleFqdnOrName -DomainController $RoleDomainController);
            if ($dbs.Length -ne 0)
            {
            Write-ExchangeSetupLog -Info ("Retrieving users with Name=$name.");
            $arbUsers = @(Get-User -Filter {name -eq $name} -IgnoreDefaultScope -ResultSize 1);
            if ($arbUsers.Length -ne 0)
            {
            Write-ExchangeSetupLog -Info ("Enabling mailbox $name.");
            $sysMbx = Enable-Mailbox -Arbitration -Identity $arbUsers[0] -DisplayName $dispName -database $dbs[0].Identity;
            }
            }
            }
            else
            {
            if ($mbxs[0].DisplayName -ne $dispName )
            {
            Write-ExchangeSetupLog -Info ("Setting DisplayName=$dispName.");
            Set-Mailbox -Arbitration -Identity $mbxs[0] -DisplayName $dispName -Force;
            }
            $sysMbx = $mbxs[0];
            }

            # Set the Organization Capabilities needed for this mailbox
            if ($sysMbx -ne $null)
            {
            # We need 1 GB for uploading large OAB files to the organization mailbox
            Write-ExchangeSetupLog -Info ("Setting mailbox properties.");
                set-mailbox -Arbitration -identity $sysMbx -UMGrammar:$true -OABGen:$true -GMGen:$true -ClientExtensions:$true -MailRouting:$true -MessageTracking:$true -MaxSendSize 1GB -Force;
            }
            else
            {
            Write-ExchangeSetupLog -Info ("Cannot find arbitration mailbox with name=$name.");
            }
            }
            else
            {
            Write-ExchangeSetupLog -Info "Skipping creating E15 System Mailbox because of insufficient permission."
            }
            }
        " was run: "Database is mandatory on UserMailbox.".

Error:
The following error was generated when "$error.Clear(); 
            if ($RoleIsDatacenter -ne $true -and $RoleIsDatacenterDedicated -ne $true)
            {
            if (Test-ExchangeServersWriteAccess -DomainController $RoleDomainController -ErrorAction SilentlyContinue)
            {
            $sysMbx = $null;
            $name = "SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}";
            $dispName = "Microsoft Exchange";
            Write-ExchangeSetupLog -Info ("Retrieving mailboxes with Name=$name.");
            $mbxs = @(Get-Mailbox -Arbitration -Filter {name -eq $name} -IgnoreDefaultScope -ResultSize 1 );
            if ($mbxs.Length -eq 0)
            {
            Write-ExchangeSetupLog -Info ("Retrieving mailbox databases on Server=$RoleFqdnOrName.");
            $dbs = @(Get-MailboxDatabase -Server:$RoleFqdnOrName -DomainController $RoleDomainController);
            if ($dbs.Length -ne 0)
            {
            Write-ExchangeSetupLog -Info ("Retrieving users with Name=$name.");
            $arbUsers = @(Get-User -Filter {name -eq $name} -IgnoreDefaultScope -ResultSize 1);
            if ($arbUsers.Length -ne 0)
            {
            Write-ExchangeSetupLog -Info ("Enabling mailbox $name.");
            $sysMbx = Enable-Mailbox -Arbitration -Identity $arbUsers[0] -DisplayName $dispName -database $dbs[0].Identity;
            }
            }
            }
            else
            {
            if ($mbxs[0].DisplayName -ne $dispName )
            {
            Write-ExchangeSetupLog -Info ("Setting DisplayName=$dispName.");
            Set-Mailbox -Arbitration -Identity $mbxs[0] -DisplayName $dispName -Force;
            }
            $sysMbx = $mbxs[0];
            }

            # Set the Organization Capabilities needed for this mailbox
            if ($sysMbx -ne $null)
            {
            # We need 1 GB for uploading large OAB files to the organization mailbox
            Write-ExchangeSetupLog -Info ("Setting mailbox properties.");
                set-mailbox -Arbitration -identity $sysMbx -UMGrammar:$true -OABGen:$true -GMGen:$true -ClientExtensions:$true -MailRouting:$true -MessageTracking:$true -MaxSendSize 1GB -Force;
            }
            else
            {
            Write-ExchangeSetupLog -Info ("Cannot find arbitration mailbox with name=$name.");
            }
            }
            else
            {
            Write-ExchangeSetupLog -Info "Skipping creating E15 System Mailbox because of insufficient permission."
            }
            }
        " was run: "Database is mandatory on UserMailbox. Property Name: Database".

Hi,
The arbitration mailbox SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c} doesn't have a database assigned and it needs to.
To fix that problem, assign one and rereun the upgrade.

Example:
Set-Mailbox -arbitration "SystemMailbox{bb558*" -targetdatabase "Database Name"

Hello,

I agree with Martina's suggestion.

Besides, please check if you have these permission "Schema Admins, Domain Admins, and Enterprise Admins".

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