Essa eu peguei na net e nem lembro....
Já pensou colocar isso no script para gerar script...
Veja o script abaixo.
============================= SCRIPT CORRIGIDO ===================================
USE <<< SEU BANCO >>>
SELECT
t.NAME AS Entidade,
p.rows AS Registros,
SUM(a.total_pages) * 8 AS EspacoTotalKB,
SUM(a.used_pages) * 8 AS EspacoUsadoKB,
(SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS EspacoNaoUsadoKB
FROM
sys.tables t
INNER JOIN
sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN
sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN
sys.allocation_units a ON p.partition_id = a.container_id
LEFT OUTER JOIN
sys.schemas s ON t.schema_id = s.schema_id
WHERE
t.NAME NOT LIKE 'dt%'
AND t.is_ms_shipped = 0
AND i.OBJECT_ID > 255
GROUP BY
t.Name, s.Name, p.Rows
ORDER BY
Registros DESC
============================= SCRIPT ANTIGO ===================================
use <SEUBANCO>
SELECT
OBJECT_NAME(object_id) As Tabela, Rows As Linhas,
SUM(Total_Pages * 8) As Reservado,
SUM(CASE WHEN Index_ID > 1 THEN 0 ELSE Data_Pages * 8 END) As Dados,
SUM(Used_Pages * 8) -
SUM(CASE WHEN Index_ID > 1 THEN 0 ELSE Data_Pages * 8 END) As Indice,
SUM((Total_Pages - Used_Pages) * 8) As NaoUtilizado
FROM
sys.partitions As P
INNER JOIN sys.allocation_units As A ON P.hobt_id = A.container_id
GROUP BY OBJECT_NAME(object_id), Rows
ORDER BY Dados desc