>A client sent me a database (.bak) file. I'm trying to restore it. I'm getting
>
>

>TITLE: Microsoft SQL Server Management Studio
>------------------------------
>
>An exception occurred while executing a Transact-SQL statement or batch. (Microsoft.SqlServer.ConnectionInfo)
>
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>ADDITIONAL INFORMATION:
>
>The media family on device 'C:\Program Files (x86)\Microsoft SQL Server\MSSQL.1\MSSQL\Backup\ER_VT_backup_2011_05_10_020001_3850000.bak' is incorrectly formed. SQL Server cannot process this media family.
>RESTORE HEADERONLY is terminating abnormally. (Microsoft SQL Server, Error: 3241)
>
>For help, click: http://go.microsoft.com/fwlink?ProdName=Microsoft+SQL+Server&ProdVer=09.00.5000&EvtSrc=MSSQLServer&EvtID=3241&LinkId=20476
>
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>BUTTONS:
>
>OK
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>

>
>Anyone know what's wrong here?

Well, most likely it's a corrupted backup. Check it with the script from this link
http://beyondrelational.com/blogs/nakul/archive/2011/04/18/a-script-to-verify-a-database-backup.aspx