And it won't restore a database backup that has more files than the database you're replacing.

I have been using the following code for generating the 'move' parameters, which handles this situation by putting new files in the default file path:

DECLARE @Move nvarchar(max);

SET @Move = NULL

SELECT @Move = COALESCE(@Move + ',

', ' ') + 'MOVE N''' + lfn.LogicalName + ''' TO N'''

+ COALESCE(mf.physical_name, -- Use filename and path from existing file

-- Or put new files in 'default paths':

CASE lfn.[Type]

WHEN 'D' THEN CONCAT(CONVERT(nvarchar(max), SERVERPROPERTY('instancedefaultdatapath')), LogicalName, '.mdf')

WHEN 'L' THEN CONCAT(CONVERT(nvarchar(max), SERVERPROPERTY('instancedefaultlogpath')), LogicalName, '.ldf')

END

) + ''''

FROM #logicalfilenames lfn

LEFT JOIN (

SELECT DatabaseName = d.name, mf.name, mf.physical_name

FROM sys.master_files mf

JOIN sys.databases d ON d.database_id = mf.database_id

) mf ON mf.name = lfn.LogicalName AND mf.DatabaseName = @dbname