Mount-SPContentDatabase -> A SharePoint database named "mycompany_PortalHome_Content" already exists. You must supply another name for the new database.

Hi,

I'm trying to migrate my Sharepoint 2010 Farm to Sharepoint 2013.

I have a problem when i try to mount the SP2010 database in SP2013. When i first tried, i had some problems that i figured out, but now, when i retry this command : "#Mount-SPContentDatabase -Name SP2010_FARM1_PortalHome_Content -WebApplication http://SP2013:80/ -AssignNewDatabaseId" i get this error message : 

"Mount-SPContentDatabase : A SharePoint database named SP2010_FARM1_PortalHome_Content already exists.  You must supply another name for the new database.
At line:72 char:1
+ Mount-SPContentDatabase -Name SP2010_FARM1_PortalHome_Content -WebApplication ht ..."

Do you know how to figure this out ? 

Few days ago i tried to update the database name in SQLSERVER -> Farm_Config -> Objects but obviously it wasn't the best idea i had. So i re-install a new Sharepoint 2013 server but now i'm facing this problem again.

Thank you for helping

Regards.