Cannot find type [Microsoft.SqlServer.Management.Smo.Server]: make sure the assembly containing this type is loaded.

Put this in profile.ps1 for example.

[System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMO')  | out-null
[System.Reflection.Assembly]::LoadWithPartialName('Microsoft.SqlServer.SMOExtended')  | out-null