Database Detach Problem

Hi all,

I'm trying to detach a database and after archive it for deliver to other server.

The detach wents fine and the database is removed from the database tree list in Management Studio. The problem is that the mdf file is being locked by some process (maybe SQL) and I can't imagine why. Here is the code for this operation:

USE master;

GO

ALTER DATABASE IMS_MCK_MIS SET AUTO_UPDATE_STATISTICS ON

GO

ALTER DATABASE IMS_MCK_MIS SET EMERGENCY

GO



DECLARE @strDate NVARCHAR(8)

DECLARE @strCmd NVARCHAR(255)

SELECT @strDate = CONVERT(nvarchar(8), GETDATE(),112)

EXEC sp_detach_db 'IMS_MCK_MIS'



SELECT @strCmd = 'wzzip -ex -m C:Deliveryarchive_' + @strDate + '.zip E:DBSQLIMS_MCK_MIS.mdf'

exec master..xp_cmdshell @strCmd



Anyone have any idea how to quickly free the mdf file?

Thanks and regards

CG