Exchange 2010 install error mailbox role failed

I am currently migrating SBS 2003 to server 2008 r2 standard with exchange 2010. I have followed this guide so far:

https://www.experts-exchange.com/Software/Server_Software/Email_Servers/Exchange/A_2881-Migrate-Small-Business-Server-2003-to-Exchange-2010-and-Windows-2008-R2.html

BTW: I am logged in as Administrator locally.

This is the error from the exchange install log

Summary: 12 item(s). 10 succeeded, 1 failed.
Elapsed time: 00:23:32


Organization Preparation
Completed

Elapsed Time: 00:02:05


Preparing Setup
Completed

Elapsed Time: 00:00:00


Stopping Services
Completed

Elapsed Time: 00:00:00


Copy Exchange Files
Completed

Elapsed Time: 00:04:22


Language Files
Completed

Elapsed Time: 00:09:12


Restoring services
Completed

Elapsed Time: 00:00:00


Languages
Completed

Elapsed Time: 00:00:00


Management Tools
Completed

Elapsed Time: 00:00:06


Hub Transport Role
Completed

Elapsed Time: 00:03:22


Client Access Role
Completed

Elapsed Time: 00:01:52


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 ) { $dmRoleGroupName = "Discovery Management"; $dmRoleGroup = Get-RoleGroup -Identity $dmRoleGroupName -DomainController $RoleDomainController -ErrorAction:SilentlyContinue; if( $dmRoleGroup -ne $null ) { Add-MailboxPermission $dismbx -User $dmRoleGroup.Identity -AccessRights FullAccess -DomainController $RoleDomainController -WarningAction SilentlyContinue; } } } }" was run: "Couldn't mount the database that you specified. Specified database: Mailbox Database 0630478852; Error code: An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: MapiExceptionNotFound: Unable to mount database. (hr=0x8004010f, ec=-2147221233)
 [Database: Mailbox Database 0630478852, Server: FQDN].".

Couldn't mount the database that you specified. Specified database: Mailbox Database 0630478852; Error code: An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: MapiExceptionNotFound: Unable to mount database. (hr=0x8004010f, ec=-2147221233)
 [Database: Mailbox Database 0630478852, Server: FQDN].

An Active Manager operation failed. Error: The database action failed. Error: Operation failed with message: MapiExceptionNotFound: Unable to mount database. (hr=0x8004010f, ec=-2147221233)
 [Database: Mailbox Database 0630478852, Server: FQDN]

An Active Manager operation failed. Error: Operation failed with message: MapiExceptionNotFound: Unable to mount database. (hr=0x8004010f, ec=-2147221233)
 [Server: FQDN]

MapiExceptionNotFound: Unable to mount database. (hr=0x8004010f, ec=-2147221233)


Elapsed Time: 00:02:27


Finalizing Setup
Cancelled


Need a little guidance.

Thanks Guys.